Men are blind in their own cause

Men are blind in their own cause.

Prov. If you believe in something very fervently, you will not recognize the flaws in what you believe or the dangers associated with it. Jill: Lyle is so intent on converting people to his religion, that he doesn't see that his constant preaching is alienating his friends. Jane: Men are blind in their own cause.
See also: blind, cause, men