Harmony of the Gospels and the Sermon on the Mount

The critic sets his sights on this sermon for a number of different reasons. They would say that this Sermon is one of the foremost evidences that the Bible is full of contradictions. Much debate has surrounded this sermon over the two centuries. From both the Christian and the Critic. I would suggest that in the same wicked ways that the Sermon on the Mount is attacked, is the same ways that entirety of the Bible is attacked.
I hope by trying to answer a few simple questions about the Sermon on the Mount, that it will shed light on all accusations and attacks on the Word of God.