Islam and the Trinity

I caught a taxi the other day as I was coming back to campus from the train station. And within 1 minuet of my saying that I was going to Moody, he had me engaged in a debate about the Trinity. He referenced Deuteronomy 6:4, Mark 10:18, John 17, and a couple other passages with very impressive speed. I gave an interpretation of each that he found unsatisfactory. And as he continued I realized the issue was not the Trinity. He had faith in Islam. I had faith in Jesus. If the Islam had a trinity, their would be other differences to focus on. The problem is that Islam is not Christianity. But a logical debate on interpretation between two people of faith is a futile thing. My taxi driver got the last word and he used to in his mind prove the illigitamacy of Christ. And we both left the conversation completely unmoved on the issue, and a little frusterated at the eachothers stubburness. I thanked God for the Holy Spirit, who is fully God, and who is the only one who can get to that mans heart.