The Qur'an denies that God begets or takes to himself offspring (Surah 112). In other places it asks, "How can Allah have a son, when he hath no consort?" (Surah 6:101). Allah "has taken neither a wife nor a son." (Surah 72:3). Such denunciation was directed primarily against the polytheism of the Makkans. However, Muslims use these passages along with passages which deal specifically with heretical trinitarian ideas to condemn the doctrine of the Sonship of Christ as they believe it is taught in Christianity (Surah 19:88-93).
Every messenger of God is a shahid (witness) to the true faith before his people. Jesus' mission as a witness is highlighted in the discourse between him and Almighty God that will take place on the day of judgement but is already written down in the Qur'an, that God will ask him whether he taught people to worship him and his mother beside God. Jesus will certainly deny this and will affirm that he had said, "Worship God, my Lord and your Lord". (Surah 5:116 - 117).
It is thought that the Qur'an also denies the doctrine of the Trinity (Surah 4:171; 5:73,116). However, what it denies is the Trinity that consists of Father, Mother and Son. Nowhere does the Bible suggest that type of trinity or that God is one of three or the third of three. Christians certainly agree that there is no god, but one God. The notion of three gods is as offensive to Christians as to Muslims.
There is nothing in the Bible which could suggest that Jesus ever spoke of Mary being taken as a god beside God. What the Qur'an re-edits is some of the heretical doctrines that were around in those days in Arabia and its neighbouring areas.
It is important to appreciate that Jesus, alone among the founders of the great religions of the world, spoke with authority. Others have claimed to speak the words they have received from God, for example, Moses begins all his teachings with the phrase, "Thus says the LORD". However, Jesus says, "But I say to you...". The people who heard him "were amazed at his teaching, because his message had authority" (Luke 4:32). No other prophet spoke with such authority. Prophets claimed to have a deeper insight into the Truth, however Jesus went further by claiming to be the Truth, the source of all Truth. In the light of his claims and deeds the Bible portrays him as the "image of the invisible God" (Col 1:15) and as the living Word of God through whom He has spoken in a way He never did before (Hebrew 1:1-3). Jesus certainly did not go around saying, "I am God". Indeed, he joyfully acknowledged his dependence upon God. However, the things he said and did convinced his contemporaries that he was stepping into the space reserved for God, acting and speaking for him in a way never seen or heard before.
Christians respond that they do not raise a mere human being to the status of being equal with God but that this Jesus before coming into this world existed with God as his Word. As God is, his Word is. It is due to the glory that Jesus had with God before becoming the Son of Mary that Christians believe in him as coexistent and coequal with God. Jesus as the Son of Mary or as Ibn Adam (the Son of Man) is God az-zahir (revealed).