How Important Is It To State The Obvious

"I have just heard your commentary about the tongue," wrote a listener.  This friend added, "I am one of those who … is brutally frank.  I know the truth is bitter, but my greatest defect is to tell a person what wrong he has done which he ought not to do.  Is it unchristian?"  It's amazing to me how many folks such as the woman who wrote feel compelled to point out people's flaws.