A Sinful Muhammad?

A Sinful Muhammad?
After I had given a lecture on Islam at the University of Texas (Austin)
in 
1991, I was challenged by some Muslim students to prove that Muhammad was
a 
sinner

My first response was to point out that the burden of proof was not on me 
but on them. I then asked, "Where in the Quran is it ever stated that 
Muhammad was sinless?"

They could not refer me to a single passage in which such an idea is even 
suggested, much less taught.

They demanded that I show from the Quran where Muhammad was said to be a 
sinner. I answered their challenge by citing several passages from the
Quran 
which clearly reveal to any honest reader that Muhammad was a sinner.