Qur'an is unequivocally, absolutely clear on Oneness of God [Allah], while some other issues are debated, Muslims are unanimous on Oneness of God [Allah] and truthfulness, originality and reliability of Qur'an as the word of God. More on Trinity at http://wp.me/PCgrB-dI
The Doctrine of the TRINITY... Mystery or Confusion?
"There is but One God, the Father." -- 1 Corinthians 8:6
All who consider the issue agree that the doctrine of the Trinity is incomprehensible. Its most ardent proponents suppose this to be a strength -- that as we cannot comprehend the majesty and glory of the infinite Creator, so we cannot fathom his nature and being. Not so. The Creator has explicitly revealed himself through His Word as a mighty, unitary being, the great first cause of all things, having no equal, no predecessor and no successor. For 4000 years those who worshiped Him and trusted Him had no hint, no surmise, no suggestion that he was other than the single, unitary God He declared Himself :
"Hear, O Israel, the LORD your God is One" (Deut. 6:4).
"Know and believe me, and understand that I am he: before me there was no God formed, neither shall there be after me. I, even I, am the LORD" (Isaiah 43:10, 11).