interesting article!
The Heresy of the Ishmaelites:
http://orthodoxinfo.com/general/stjohn_islam.aspx
My favorite part:
When we ask again: ‘How is it that when he enjoined us in this book of yours not to do anything or receive anything without witnesses, you did not ask him: “First do you show us by witnesses that you are a prophet and that you have come from God, and show us just what Scriptures there are that testify about you”’—they are ashamed and remain silent. [Then we continue:] ‘Although you may not marry a wife without witnesses, or buy, or acquire property; although you neither receive an ass nor possess a beast of burden unwitnessed; and although you do possess both wives and property and asses and so on through witnesses, yet it is only your faith and your scriptures that you hold unsubstantiated by witnesses. For he who handed this down to you has no warranty from any source, nor is there anyone known who testified about him before he came. On the contrary, he received it while he was asleep.’