The Muslim scripture describes Allah as the Creators of all things:
Is it ye who create it, or are We the Creators (nahnu al-khaliqoona)? S. 56:59 Y. Ali
I am going to show that this isn’t merely a case of plural of intensification or majestic plural. Rather, the plural description is employed precisely because Allah is depicted as consisting of multiple persons or because he exists in union with other divine beings.
For instance, Jesus in the Islamic scripture creates and breathes life into inanimate clay objects,
When the angels said, ‘Mary, God gives thee good tidings of a Word from Him whose name is Messiah, Jesus, son of Mary; high honoured shall he be in this world and the next, near stationed to God.He shall speak to men in the cradle, and of age, and righteous he shall be.’ ‘Lord,’ said Mary, ‘how shall I have a son seeing no mortal has touched me?’ ‘Even so,’ God said, ‘God creates what He will. When He decrees a thing He does but say to it “Be,” and it is. And He will teach him the Book, the Wisdom, the Torah, the Gospel, to be a Messenger to the Children of Israel saying, “I have come to you with a sign from your Lord. I WILL CREATE for you out of CLAY (anni AKHLUQU lakum mina al-TINI) as the likeness of a bird; then I WILL BREATHE (fa-anfukhu) into it, and it will be a bird, by the leave of God. I will also heal the blind and the leper, and bring to life the dead, by the leave of God. I will inform you too of what things you eat, and what you treasure up in your houses. Surely in that is a sign for you, if you are believers. S. 3:45-49 Arberry
When God said, ‘Jesus Son of Mary, remember My blessing upon thee and upon thy mother, when I confirmed thee with the Holy Spirit, to speak to men in the cradle, and of age; and when I taught thee the Book, the Wisdom, the Torah, the Gospel; and when THOU CREATEST out of CLAY (wa-idh TAKHLUQU mina al-TINI, by My leave, as the likeness of a bird, and THOU BREATHEST (fatanfukhu) into it, and it is a bird, by My leave; and thou healest the blind and the leper by My leave, and thou bringest the dead forth by My leave; and when restrained from thee the Children of Israel when thou camest unto them with the clear signs, and the unbelievers among them said, “This is nothing but sorcery manifest. S. 5:110 Arberry
In the exact same fashion that Allah created and breathed life into the clay body of Adam:
Behold, thy Lord said to the angels: “I am about to create (inni khaliqun) man from clay (tinin): When I have fashioned him (in due proportion) and breathed (wanafakhtu) into him of My spirit, fall ye down in obeisance unto him.” S. 38:71-72 Y. Ali
The Quran also describes the Holy Spirit or Spirit of Allah who is sent to create and give life:
(Muhammad), mention in the Book (the Quran) the story of Mary how she left her family and started living in a solitary place to the East out of her people’s sight. We sent Our Spirit to her, who stood before her in the shape of a well formed human being. Mary said, “Would that the Beneficent God would protect me from you. Leave me alone if you are a God fearing person”. He said, “I am the Messengers of your Lord. I have come to give you a purified son.” S. 19:16-19 (Muhammad Sarwar http://www.islamawakened.com/quran/19/st23.htm)
And Mary, the daughter of Imran, who guarded her private parts, so We breathed into it of Our Spirit and she established as true the Words of her Lord and His Books and she had been among the ones who are morally obligated. S. 66:12 (Dr. Laleh Bakhtiar http://www.islamawakened.com/quran/66/st46.htm)
In these examples, the Spirit appears to Mary as a perfect looking man to announce to her that he was sent to give her an absolutely pure son. The Spirit did this when he was then breathed into Mary’s body in order to cause her to conceive Jesus in her blessed womb.
Allah also breathed his Spirit into Adam,
And when thy Lord said to the angels, ‘See, I am creating a mortal of a clay of mud moulded. When I have shaped him, and breathed My spirit in him, fall you down, bowing before him!’ S. 15:28-29 Arberry
For the obvious purpose of animating Adam’s body so he could become a living being. This shows that the Spirit is the personal divine breath of God through whom God creates and imparts life.
The Holy Spirit was also sent to strengthen Jesus during his earthly ministry,
When Allah saith: O Jesus, son of Mary! Remember My favour unto thee and unto thy mother; how I strengthened thee with the holy Spirit, so that thou spakest unto mankind in the cradle as in maturity; and how I taught thee the Scripture and Wisdom and the Torah and the Gospel; and how thou didst shape of clay as it were the likeness of a bird by My permission, and didst blow upon it and it was a bird by My permission, and thou didst heal him who was born blind and the leper by My permission; and how thou didst raise the dead by My permission; and how I restrained the Children of Israel from (harming) thee when thou camest unto them with clear proofs, and those of them who disbelieved exclaimed: This is naught else than mere magic; S. 5:110 Pickthall – cf. Q. 2:87, 253
Here we have an explicit reference to an Islamic version of the Triunity, i.e., God/Allah, Jesus and the Holy Spirit all working together as Jesus carries out his earthly mission.
Once again, the Quran is doing nothing other than parrot the Holy Bible at this point:
“Jesus returned in the power of the Spirit to Galilee. And His fame went throughout the surrounding region. He taught in their synagogues, being glorified by everyone. He came to Nazareth, where He had been brought up. And as His custom was, He went to the synagogue on the Sabbath day. And He stood up to read. The scroll of the prophet Isaiah was handed to Him. When He had unrolled the scroll, He found the place where it was written: ‘The SPIRIT of the LORD is upon ME, because He has anointed Me to preach the gospel to the poor; He has sent Me to heal the broken-hearted, to preach deliverance to the captives and recovery of sight to the blind, to set at liberty those who are oppressed; to preach the acceptable year of the Lord.’ Then He rolled up the scroll, and He gave it back to the attendant, and sat down. The eyes of all those who were in the synagogue were fixed on Him. And He began to say to them, ‘Today this Scripture is fulfilled in your hearing.’” Luke 4:14-21
“The word which He sent to the children of Israel, preaching peace through Jesus Christ, who is Lord of all, the word, which you know, that was proclaimed throughout all Judea, beginning from Galilee after the baptism which John preached: how GOD anointed JESUS of Nazareth with the HOLY SPIRIT and with power, who went about doing good and healing all who were oppressed by the devil, for GOD was with HIM.” Acts 10:36-38
The Spirit is further sent to strengthened believers to remain faithful to the will of God:
Thou wilt not find folk who believe in Allah and the Last Day loving those who oppose Allah and His messenger, even though they be their fathers or their sons or their brethren or their clan. As for such, He hath written faith upon their hearts and hath strengthened them with a Spirit from Him, and He will bring them into Gardens underneath which rivers flow, wherein they will abide. Allah is well pleased with them, and they are well pleased with Him. They are Allah’s party. Lo! is it not Allah’s party who are the successful? S. 58:22 Pickthall
In order for the Spirit to strengthen all believers everywhere, he must be omniscient, omnipresent, and omnipotent. Yet the only way the Spirit could possess such attributes as if he is fully divine in essence, a fact that is even admitted by the late Muslim translator and commentator Abdullah Yusuf Ali:
“… Cf. ii 87 and 253, where it is said that God strengthened the Prophet Jesus with the holy spirit. Here we learn that all good and righteous men are strengthened by God with the holy spirit. If anything, the phrase used here is stronger, ‘a spirit from Himself’. Whenever any one offers his heart in faith and purity to God, God accepts it, engraves that faith on the seeker’s heart, and further fortifies him with THE DIVINE SPIRIT, which we can no more adequately define in human language the nature of God.” (Ali, The Meaning of the Holy Quran, p. 1518, fn. 5365; bold and capital emphasis mine)
So herein is the Quran’s triple creators, namely, Allah, his word Jesus whom he sent down to become a human being from the virgin Mary, and the Holy Spirit:
O ye people of the Book! do not exceed in your religion, nor say against God aught save the truth. The Messiah, Jesus the son of Mary, is but the apostle of God and His Word, which He cast into Mary and a spirit from Him; believe then in God and His apostles, and say not ‘Three.’ Have done! it were better for you. God is only one God, celebrated be His praise that He should beget a Son! His is what is in the heavens and what is in the earth; and God sufficeth for a guardian. S. 4:171 Palmer
This either means Allah, Jesus and the Spirit of Allah are essentially one, and therefore eternally coexist as one divine being. Or Allah, Christ and the Spirit are separate gods, one of whom also became human. There’s simply no way around this.