The Maker must be one, since if there were two they would necessarily either concur or not concur in their creating. Now agreement would be evidence of the weakness of both or either of them, since a free agent does not agree except by compulsion, and if they differed, then either they would each attain their desire — and absurdity — or they would not attain it, which would mean their impotence, and a weakling is not suitable as a Lord. This taken from God’s Word, exalted be He: “If there were gods other than God in heaven or earth, they would both go to ruin” (Sura 21:22). — from “A Creedal Statement of Al-Maturidi”
Muhammad Abu Mansur al-Maturidi (853–944) was an Iranian Muslim theologian who specialized in Islamic law and exegesis of the Koran. Considered a pioneer in the field of Islamic jurisprudence, his work is considered authoritative and he holds a high standing among Islamic scholars. Veering from his contemporaries on the question of whether God created the human power and will to act as well as human action itself, Al-Maturidi held that only the power was created by God, but the human will was free to act on his own.