The following is the material I prepared for my debate with a Mormon. All bold and capital emphasis will be mine.
SMITH THE POLYTHEIST
The Gods plan the creation of the earth and all life thereon—Their plans for the six days of creation are set forth.
And then the Lord said: Let us go down. And they went down at the beginning, and they, that is the Gods, organized and formed the heavens and the earth. And the earth, after it was formed, was empty and desolate, because they had not formed anything but the earth; and darkness reigned upon the face of the deep, and the Spirit of the Gods was brooding upon the face of the waters. And they (the Gods) said: Let there be light; and there was light. And they (the Gods) comprehended the light, for it was bright; and they divided the light, or caused it to be divided, from the darkness… And the Gods took counsel among themselves and said: Let us go down and form man in our image, after our likeness; and we will give them dominion over the fish of the sea, and over the fowl of the air, and over the cattle, and over all the earth, and over every creeping thing that creepeth upon the earth. So the Gods went down to organize man in their own image, in the image of the Gods to form they him, male and female to form they them. And the Gods said: We will bless them. And the Gods said: We will cause them to be fruitful and multiply, and replenish the earth, and subdue it, and to have dominion over the fish of the sea, and over the fowl of the air, and over every living thing that moveth upon the earth… And the Gods said: We will do everything that we have said, and organize them; and behold, they shall be very obedient. And it came to pass that it was from evening until morning they called night; and it came to pass that it was from morning until evening that they called day; and they numbered the asixth time. (The Book of Abraham, 4:1-4, 26-28, 31 https://www.churchofjesuschrist.org/study/scriptures/pgp/abr/4?lang=eng)
SMITH DENIED THE ETERNALITY AND IMMUTABILITY OF GOD. HE CLAIMED GOD WAS ACTUALLY A MAN LIKE US.
The following quotation from the King Follet’s Discourse is taken from Robert M. Bowman Jr., The Mormon God Has Not Always Been God, Part One: Joseph Smith’s King Follett Discourse, posted on August 26, 2013 (http://mit.irr.org/mormon-god-has-not-always-been-god-part-1).
God himself was once as we are now, and is an exalted man, and sits enthroned in yonder heavens! That is the great secret. If the veil were rent today, and the great God who holds this world in its orbit, and who upholds all worlds and all things by His power, was to make himself visible—I say, if you were to see him today, you would see him like a man in form—like yourselves in all the person, image, and very form as a man; for Adam was created in the very fashion, image and likeness of God, and received instruction from, and walked, talked and conversed with Him, as one man talks and communes with another.
In order to understand the subject of the dead, for consolation of those who mourn for the loss of their friends, it is necessary we should understand the character and being of God and how He came to be so; for I am going to tell you how God came to be God. We have imagined and supposed that God was God from all eternity. I will refute that idea, and take away the veil, so that you may see.
These ideas are incomprehensible to some, but they are simple. It is the first principle of the Gospel to know for a certainty the Character of God, and to know that we may converse with Him as one man converses with another, and that He was once a man like us; yea, that God himself, the Father of us all, dwelt on an earth, the same as Jesus Christ Himself did; and I will show it from the Bible.
I wish I was in a suitable place to tell it, and that I had the trump of an archangel, so that I could tell the story in such a manner that persecution would cease forever. What did Jesus say? (Mark it, Elder Rigdon!) The scriptures inform us that Jesus said, as the Father hath power in himself, even so hath the Son power—to do what? Why, what the Father did. The answer is obvious—in a manner to lay down his body and take it up again. Jesus, what are you going to do? To lay down my life as my Father did, and take it up again. Do you believe it? If you do not believe it you do not believe the Bible. The scriptures say it, and I defy all the learning and wisdom and all the combined powers of earth and hell together to refute it.
Here, then, is eternal life—to know the only wise and true God; and you have got to learn how to be gods yourselves, and to be kings and priests to God, the same as all gods have done before you, namely, by going from one small degree to another, and from a small capacity to a great one; from grace to grace, from exaltation to exaltation, until you attain to the resurrection of the dead, and are able to dwell in everlasting burnings, and to sit in glory, as do those who sit enthroned in everlasting power. And I want you to know that God, in the last days, while certain individuals are proclaiming His name, is not trifling with you or me. (“King Follett Discourse,” April 7, 1844, as quoted in Teachings of the Prophet Joseph Smith, comp. Joseph Fielding Smith (Salt Lake City: Deseret, 1976), 345-47. The entire sermon was also published and is available online at LDS.org in an article in the Ensign, April 1971. Parts of this sermon are quoted in “The Fulness of the Gospel: The Nature of the Godhead,” Ensign, Jan. 2006; “Chapter 2: God the Father,” in Teachings of Presidents of the Church: Joseph Smith (2011), 36–44; and in many other sources throughout LDS history.)
SMITH AFFIRMS GOD’S ETERNAL IMMUTABILITY
By these things we know that there is a God in heaven, who is infinite and eternal, from everlasting to everlasting the same unchangeable God, the framer of heaven and earth, and all things which are in them. (Doctrines and Covenants 20:17 https://www.churchofjesuschrist.org/study/scriptures/dc-testament/dc/20.17?lang=eng#p17#17)
From eternity to eternity he is the same, and his years never fail. (Doctrines and Covenants 76:4 https://www.churchofjesuschrist.org/study/scriptures/dc-testament/dc/76.4?lang=eng#p4#4)
For behold, God aknowing all things, being from beverlasting to everlasting, behold, he sent cangels to minister unto the children of men, to make manifest concerning the coming of Christ; and in Christ there should come every good thing. (Moroni 7:22 https://www.churchofjesuschrist.org/study/scriptures/bofm/moro/7?lang=eng)
For I know that God is not a partial God, neither a changeable being; but he is aunchangeable from ball eternity to all eternity. (Moroni 8:18 https://www.churchofjesuschrist.org/study/scriptures/bofm/moro/8?lang=eng)
For behold, the time cometh, and is not far distant, that with power, the Lord Omnipotent who reigneth, who was, and is from all eternity to all eternity, shall come down from heaven among the children of men, and shall dwell in a tabernacle of clay, and shall go forth amongst men, working mighty miracles, such as healing the sick, raising the dead, causing the lame to walk, the blind to receive their sight, and the deaf to hear, and curing all manner of diseases. (Mosiah 3:5 https://www.churchofjesuschrist.org/study/scriptures/bofm/mosiah/3?lang=eng)
This high priesthood being after the order of his Son, which order was from the foundation of the world; or in other words, being without beginning of days or end of years, being prepared from eternity to all eternity, according to his foreknowledge of all things- (Alma 13:7 https://www.churchofjesuschrist.org/study/scriptures/bofm/alma/13?lang=eng)
SMITH THE ORTHODOX TRINITARIAN
And it came to pass that while the angels were ministering unto the disciples, behold, Jesus came and stood in the midst and ministered unto them. And it came to pass that he spake unto the multitude, and commanded them that they should kneel down again upon the earth, and also that his disciples should kneel down upon the earth. And it came to pass that when they had all knelt down upon the earth, he commanded his disciples that they should pray. And behold, they began to pray; and they did pray unto Jesus, calling him their Lord and their God. And it came to pass that Jesus departed out of the midst of them, and went a little way off from them and abowed himself to the earth, and he said: Father, I thank thee that thou hast given the Holy Ghost unto these whom I have achosen; and it is because of their belief in me that I have chosen them out of the world. Father, I pray thee that thou wilt give the Holy Ghost unto all them that shall believe in their words. Father, thou hast given them the Holy Ghost because they believe in ame; and thou seest that they believe in me because thou hearest them, and they pray unto me; and they pray unto me because I am with them. And now Father, I apray unto thee for them, and also for all those who shall believe on their words, that they may believe in me, that I may be in them bas thou, Father, art in me, that we may be cone. And it came to pass that when Jesus had thus prayed unto the Father, he came unto his disciples, and behold, they did still continue, without ceasing, to pray unto him; and they did not amultiply many words, for it was given unto them what they should bpray, and they were filled with desire. And it came to pass that Jesus blessed them as they did pray unto him; and his acountenance did smile upon them, and the light of his bcountenance did cshine upon them, and behold they were as dwhite as the countenance and also the garments of Jesus; and behold the whiteness thereof did exceed all the whiteness, yea, even there could be nothing upon earth so white as the whiteness thereof. And Jesus said unto them: Pray on; nevertheless they did not cease to pray. And he turned from them again, and went a little way off and bowed himself to the earth; and he prayed again unto the Father, saying: Father, I thank thee that thou hast apurified those whom I have chosen, because of their faith, and I pray for them, and also for them who shall believe on their words, that they may be purified in me, through faith on their words, even as they are purified in me. Father, I pray not for the world, but for those whom thou hast given me aout of the world, because of their faith, that they may be purified in me, that I may be in them as thou, Father, art in me, that we may be one, that I may be glorified in them. And when Jesus had spoken these words he came again unto his disciples; and behold they did pray steadfastly, without ceasing, unto him; and he did smile upon them again; and behold they were awhite, even as Jesus. And it came to pass that he went again a little way off and prayed unto the Father; And tongue cannot speak the words which he prayed, neither can be awritten by man the words which he prayed. And the multitude did hear and do bear record; and their ahearts were open and they did understand in their hearts the words which he prayed. Nevertheless, so great and marvelous were the words which he prayed that they cannot be written, neither can they be auttered by man. And it came to pass that when Jesus had made an end of praying he came again to the disciples, and said unto them: aSo great bfaith have I never seen among all the Jews; wherefore I could not show unto them so great cmiracles, because of their unbelief. Verily I say unto you, there are none of them that have seen so great things as ye have seen; neither have they heard so great things as ye have heard. (3 Nephi 19:15-36 https://www.churchofjesuschrist.org/study/scriptures/bofm/3-ne/19?lang=eng)
SMITH THE MONOTHEISTIC MODALIST
Luke 10:23 All things are delivered to me of my Father; and no man knoweth that the Son IS the Father, and the Father IS the Son, but him to whom the Son will reveal it. (Joseph Smith Jr., Inspired Revision of the King James Version: Containing the Old and New Testaments http://www.centerplace.org/hs/iv/iv-luk.htm#c10)
Matt 11:28 All things are delivered unto me of my Father; and no man knoweth the Son, but the Father; neither knoweth any man the Father, save the Son and they to whom the Son will reveal himself; they shall see the Father also. (Ibid., http://www.centerplace.org/hs/iv/iv-mat.htm#c11)
Which Father, Son, and Holy Ghost are one God, infinite and eternal, without end. Amen. (Doctrines and Covenants 20:28 https://www.churchofjesuschrist.org/study/scriptures/dc-testament/dc/20.28?lang=eng#p28#28)
And I have a work for thee, Moses, my son; and thou art in the similitude of mine Only Begotten; and mine Only Begotten is and shall be the Savior, for he is full of grace and truth; but there is no God beside me, and all things are present with me, for I know them all. (The Book of Moses 1:6 https://www.churchofjesuschrist.org/study/scriptures/pgp/moses/1?lang=eng)
… And we know that if we are faithful in Christ, we shall rid our garments of the blood of all men, and be found spotless before the judgment-seat of Christ, and shall dwell with him eternally in the heavens. And the honor be to the Father, and to the Son, and to the Holy Ghost, which is one God. Amen. (Testimony of the Three Witnesses https://www.churchofjesuschrist.org/study/scriptures/bofm/three?lang=eng)
Believest thou that there is no God? I say unto you, Nay, thou knowest that there is a God, but thou lovest that lucre more than him. And now thou hast lied before God unto me. Thou saidst unto me—Behold these six onties, which are of great worth, I will give unto thee—when thou hadst it in thy heart to retain them from me; and it was only thy desire that I should deny the true and living God, that thou mightest have cause to destroy me. And now behold, for this great evil thou shalt have thy reward. And Zeezrom said unto him: Thou sayest there is a true and living God? And Amulek said: Yea, there is a true and living God. Now Zeezrom said: Is there more than one God? And he answered, NO. Now Zeezrom said unto him again: How knowest thou these things? And he said: An angel hath made them known unto me. And Zeezrom said again: Who is he that shall come? Is it the Son of God? And he said unto him, Yea… Now Zeezrom said unto the people: See that ye remember these things; for he said there is but one God; yet he saith that the Son of God shall come, but he shall not save his people—as though he had authority to command God… Now Zeezrom saith again unto him: Is the Son of God the very Eternal Father? And Amulek said unto him: Yea, he is the very Eternal Father of heaven and of earth, and all things which in them are; he is the beginning and the end, the first and the last; And he shall come into the world to redeem his people; and he shall take upon him the transgressions of those who believe on his name; and these are they that shall have eternal life, and salvation cometh to none else… Now, this restoration shall come to all, both old and young, both bond and free, both male and female, both the wicked and the righteous; and even there shall not so much as a hair of their heads be lost; but every thing shall be restored to its perfect frame, as it is now, or in the body, and shall be brought and be arraigned before the bar of Christ the Son, and God the Father, and the Holy Spirit, which is one Eternal God, to be judged according to their works, whether they be good or whether they be evil. (Alma 11:24-33, 35-40, 44 https://www.churchofjesuschrist.org/study/scriptures/bofm/alma/11?lang=eng)
How Christ is both the Father and the Son—He will make intercession and bear the transgressions of His people—They and all the holy prophets are His seed—He brings to pass the Resurrection—Little children have eternal life. About 148 B.C.
And now Abinadi said unto them: I would that ye should understand that God himself shall come down among the children of men, and shall redeem his people. And because he dwelleth in flesh he shall be called the Son of God, and having subjected the flesh to the will of the Father, being the Father and the Son-The Father, because he was conceived by the power of God; and the Son, because of the flesh; thus becoming the Father and Son-And they are one God, yea, the very Eternal Father of heaven and of earth. (Mosiah 15:1-4 https://www.churchofjesuschrist.org/study/scriptures/bofm/mosiah/15?lang=eng)
Teach them that redemption cometh through Christ the Lord, who is the very Eternal Father. Amen. (Mosiah 16:15 https://www.churchofjesuschrist.org/study/scriptures/bofm/mosiah/16?lang=eng)
And also that ye might know of the coming of Jesus Christ, the Son of God, the Father of heaven and of earth, the Creator of all things from the beginning; and that ye might know of the signs of his coming, to the intent that ye might believe on his name. (Helaman 14:12 https://www.churchofjesuschrist.org/study/scriptures/bofm/hel/14?lang=eng)
Behold, I am he who was prepared from the foundation of the world to redeem my people. Behold, I am Jesus Christ. I am the Father and the Son. In me shall all mankind have life, and that eternally, even they who shall believe on my name; and they shall become my sons and my daughters. And never have I showed myself unto man whom I have created, for never has man believed in me as thou hast. Seest thou that ye are created after mine own image? Yea, even all men were created in the beginning after mine own image. Behold, this body, which ye now behold, is the body of my spirit; and man have I created after the body of my spirit; and even as I appear unto thee to be in the spirit will I appear unto my people in the flesh. (Ether 3:14-16 https://www.churchofjesuschrist.org/study/scriptures/bofm/ether/3?lang=eng)
And in that day that they shall exercise faith in me, saith the Lord, even as the brother of Jared did, that they may become sanctified in me, then will I manifest unto them the things which the brother of Jared saw, even to the unfolding unto them all my revelations, saith Jesus Christ, the Son of God, the Father of the heavens and of the earth, and all things that in them are… Come unto me, O ye house of Israel, and it shall be made manifest unto you how great things the Father hath laid up for you, from the foundation of the world; and it hath not come unto you, because of unbelief. (Ether 4:7, 12 https://www.churchofjesuschrist.org/study/scriptures/bofm/ether/4?lang=eng)
And behold, the third time they did understand the voice which they heard; and it said unto them: Behold my Beloved Son, in whom I am well pleased, in whom I have glorified my name—hear ye him. And it came to pass, as they understood they cast their eyes up again towards heaven; and behold, they saw a Man descending out of heaven; and he was clothed in a white robe; and he came down and stood in the midst of them; and the eyes of the whole multitude were turned upon him, and they durst not open their mouths, even one to another, and wist not what it meant, for they thought it was an angel that had appeared unto them. And it came to pass that he stretched forth his hand and spake unto the people, saying: Behold, I am Jesus Christ, whom the prophets testified shall come into the world. And behold, I am the light and the life of the world; and I have drunk out of that bitter cup which the Father hath given me, and have glorified the Father in taking upon me the sins of the world, in the which I have suffered the will of the Father in all things from the beginning… And it came to pass that the Lord spake unto them saying: Arise and come forth unto me, that ye may thrust your hands into my side, and also that ye may feel the prints of the nails in my hands and in my feet, that ye may know that I am the God of Israel, and the God of the whole earth, and have been slain for the sins of the world… And after this manner shall ye baptize in my name; for behold, verily I say unto you, that the Father, and the Son, and the Holy Ghost ARE ONE; and I am in the Father, and the Father in me, and the Father and I are one… And this is my doctrine, and it is the doctrine which the Father hath given unto me; and I bear record of the Father, and the Father beareth record of me, and the Holy Ghost beareth record of the Father and me; and I bear record that the Father commandeth all men, everywhere, to repent and believe in me… Verily, verily, I say unto you, that this is my doctrine, and I bear record of it from the Father; and whoso believeth in me believeth in the Father also; and unto him will the Father bear record of me, for he will visit him with fire and with the Holy Ghost. And thus will the Father bear record of me, and the Holy Ghost will bear record unto him of the Father and me; for the Father, and I, and the Holy Ghost are one. (3 Nephi 11:6-10, 13-14, 27, 32, 35-36 https://www.churchofjesuschrist.org/study/scriptures/bofm/3-ne/11?lang=eng)
SMITH REDEFINED GRACE AND CONTRADICTED THE APOSTLE PAUL
For we labor diligently to write, to persuade our children, and also our brethren, to believe in Christ, and to be reconciled to God; for we know that it is by grace that we are saved, after all we can do. And, notwithstanding we believe in Christ, we keep the law of Moses, and look forward with steadfastness unto Christ, until the law shall be fulfilled. (2 Nephi 25:23-24 https://www.churchofjesuschrist.org/study/scriptures/bofm/2-ne/25?lang=eng)
That through his atonement, and by obedience to the principles of the gospel, mankind might be saved. (Doctrines and Covenants, 138:4 https://www.churchofjesuschrist.org/study/scriptures/dc-testament/dc/138.4?lang=eng#p4#4)
“For by grace are ye saved through faith; and that not of yourselves: it is the gift of God: not of works, lest any man should boast. For we are his workmanship, created in Christ Jesus unto good works, which God hath before ordained that we should walk in them.” Ephesians 2:8-10
“For we ourselves also were sometimes foolish, disobedient, deceived, serving divers lusts and pleasures, living in malice and envy, hateful, and hating one another. But after that the kindness and love of God our Saviour toward man appeared, not by works of righteousness which we have done, but according to his mercy he saved us, by the washing of regeneration, and renewing of the Holy Ghost; which he shed on us abundantly through Jesus Christ our Saviour; that being justified by his grace, we should be made heirs according to the hope of eternal life.”