No monk should ever defend another in the monastery. Nor should he take sides in an argument. Such conduct should never occur in the monastery under any circumstances because it causes very grave scandal. If anyone should violate this rule, let him be severely punished.
Wow. Severely punished. And just for defending a fellow monk. There’s got to be more here than meets the eye.
Saint Benedict is talking about cliques and the grumbling that inevitably accompanies them. When you take a side in an argument (not a discussion, mind you, but an actual confrontation) you take a personal disagreement and make it into a public one. Something that might well have been settled quietly must now be publicly and officially resolved. This is especially inappropriate for a monk because, you remember, even when he is given an impossible task, he shouldn’t defend himself; so on what grounds could he possibly dare to defend someone else?
But taking sides in a fight is always dangerous—and not just because you might end up with a black market nose-job. Morally speaking, it’s also dangerous. How, for example, do you decide which brothers are worth defending? Just the ones you agree with? The ones you’re related to? The ones you like the most? And are you sure you know all the details? You see where this is going: once you start taking sides, there’s no good reason to stop.
But what makes this behavior even more deplorable is that you are, on a personal level, playing God. Jesus said, “Do not judge, or you will be judged” (Matt 7:1). By this, of course, he did not mean that we should just accept everyone’s behavior as-is. We are called to make judgments about particular acts. We are permitted—in fact, we are obliged—to analyze certain moral acts and determine whether they conform to Christian moral standards. We can say, “…this or that act is sinful…” even “..this or that person committed a sinful act.” What we are forbidden to say is, “This is a bad person” or “This person is going to Hell.” The distinction is subtle, but necessary. We judge acts, not people.
Here’s the catch, though: you don’t judge people when they’re in the wrong, but you don’t judge them when they’re in the right either. In the old days, everyone seemed pretty confident their neighbors were going to Hell. These days, everyone seems pretty confident they’re going to Heaven. Either way, it’s not our call. That’s why we pray for the dead and not to them.
 Parents, religious superiors, and judges are sometimes called upon to judge people, but they do so with fear and trembling, knowing that they will be held accountable by God Himself.