“Every sentence of Pythagoras, like most of the ancient maxims, has a dual significance; and, while it had an occult physical meaning, expressed literally in its words, it embodied a moral precept, which is explained by Iamblichus in his Life of Pythagoras. This ‘Dig not fire with a sword’ is the ninth symbol in the Protreptics of this Neo-platonist. ‘This symbol,’ he says, ‘exhorts to prudence.’ It shows ‘the propriety of not opposing sharp words to a man full of fire and wrath—not contending with him. For frequently by uncivil words you will agitate and disturb an ignorant man, and you will suffer yourself… Herakleitus also testifies to the truth of this symbol. For, he says, “It is difficult to fight with anger, for whatever is necessary to be done redeems the soul.” And this he says truly. For many, by gratifying anger, have changed the condition of their soul.’” ~H. P. Blavatsky
Some people feel that if you see someone doing wrong, or talking rudely, you have an obligation to object to their behavior in the hope that you can get them to change, or at least convince others nearby to not follow in their path. Others will say that we should not interfere and just ignore the person because it is not our business. The correct path is somewhere in the middle.
If we see a person who gives the impression of being a generally good person, or at least a reasonable person, saying or doing something that is clearly wrong, we should, gently and politely, inform him of the error of his ways. He may be insulted at first, but upon thinking about it later on, he may very well realize that you were correct.
On the other hand, if we see a person who is argumentative, confrontational, and generally obnoxious, to try to confront him about it is probably worthless, and possibly dangerous. This type of person thrives on confrontation and loves to be challenged so he can argue his side without ever listening to what the other person has to say. What’s more, if he appears to be losing the argument, he may actually become violent in defending his belief. Even if he doesn’t become physically violent, he may be sending violent and negative thoughts toward you and the negative energy carried in those thoughts can weaken you.
These days we have a new variation of this rude and obnoxious person known as internet trolls. This are people who have noting nice to say about anyone or anything. They in fact have nothing of significance to say at all, so instead spend as much time as they can criticizing others in the vilest terms for almost anything they say. It is very tempting many times to reply to them, but it usually isn’t worth while. They almost certainly will not listen, and if they truly believe they things they post, they will get angry with you contradicting them and send negative energy to you. So very often, the best approach with this people is to just ignore them.
Of course, there are always extreme cases in which you must, as a human being and a child of God, interfere no matter what. This is when the person is not just being rude and argumentative, but is actually doing physical violence to another. You should then try to stop in whatever way you can, preferably by calling police over, but getting involved yourself if you have to.