We cannot avoid judging. As the stock in trade of the mind, appraisals are inevitable. If we were witnesses to a flagrant violation of law in which innocent people were harmed, could we keep quiet because we are not to judge?
Does not Jesus command us to judge in verse 6? "Do not give what is holy to the dogs; nor cast your pearls before swine, lest they trample them under their feet, and turn and tear you in pieces." Do we not have to judge who are "dogs" or "swine"? Considering verse 15 ("Beware of false prophets, who come to you in sheep's clothing, but inwardly they are ravenous wolves"), do we not have to judge whether a man is a false minister? Do we not have to reject his teaching based on an appraisal of his fruits?
We must therefore take care to understand clearly what Jesus meant. He obviously did not mean we should not judge at all. Within the context of Luke 6:35-38, Jesus uses "Judge not, and you shall not be judged" to urge us to love our enemies, be merciful, forgiving, and generous. This very greatly modifies Matthew's account, showing that "Judge not . . ." is a warning against self-righteous severity, sharp-tongued criticism, and condemnation. Thus, it is not a command to be absolutely neutral and tolerant regarding moral issues, but a warning to be careful and loving when we judge. We can apply this admonishment to Romans 14:10-13 and James 4:11-12 as well.
There are practical reasons why Jesus would advise us about this. Of prime importance is that even though it is important that we judge rightly, it is even more important that we do not usurp the place of God! "Who are you to judge another's servant? To his own master he stands or falls. Indeed, he will be made to stand, for God is able to make him stand" (Romans 14:4).
Paul begins this letter to the Romans calling himself a servant of Jesus Christ. He reminds us that we are all His servants (verses 7-8). A servant does not have the same rights and responsibilities as a master. Though we are permitted the right of making an appraisal of conduct, we are not permitted the right of passing judgment upon a fellow servant. A fellow servant does not stand or fall at the bar of our judgment. The only judgment that matters is the judgment of our mutual Master. If He is satisfied or displeased, He will act in His good time and in His way. To usurp His responsibility is an act of sheer presumption.
This in no way means we cannot approach a brother to inquire about and understand his conduct so that we might know whether our appraisal is correct. Assuming that our intent in questioning him is for his good, why would we even approach him? Would it not be because our evaluation of his conduct had led us to conclude—yes, to judge—that he was in serious moral or spiritual trouble?