Many attempt to use Romans 2 as proof that we are not to "judge one another" - but that is yet another misunderstanding about the writings of Paul. It's true that YOU can't arbitrarily go around enforcing your own morals on someone, or add your own judgments to those already established in the Torah (which is what "judging" is).
TORAH is our judge, and if you see a brother or sister who has fallen head-long into sin, you can't just stand by and watch, or attempt to "pray it away." You MUST warn that person, or else their blood will be on your hands. But, simply telling someone they're breaking ELOHIM's rules is NOT "judging"!
For a thorough examination of "judging" please check out our website's article.