Phineas was the Zealot, the one character in the Torah who was what we would call an extremist, a jihadi.
Yet we mention Phineas’ name at every Brit, every circumcision and we say that the only blood we are commanded to shed is in the rite of circumcision (outside of the Temple killing animals for food, is an option). And that he was able to appease the anger if God. Phineas is named together with Elijah the messenger of peace even if once he was not.
We naturally recoil from shedding blood. We are forbidden to drink it as well as shed it. Most of us are find it hard to listen to a child cry during circumcision. Yet we are commanded to do it. To shed a drop of blood, Hatafat Dam Brit, which means literally just a drop of blood.
It is a symbol of the fact that life is fragile. That blood is precious. And that in life this child will face hardships and we as parents will be forced to discipline and be tough. But the result will be that if we are committed enough, zealous enough, it will be repaid in the future of our children and in passing our commitment on to them.
We so strongly disapprove of zealots who take the law into their own hands and murder and torture in the name of religion, no matter which religion it is. It is why we now insist on the law and accepting the self-control that Torah imposes on us. We no longer allow individual decision making on such issues any more than we do in civil law. As the great Babylonian sage Samuel said, “The Law of the Land is the Law,” not what any individual thinks it ought to be.
But sometimes to preserve our faith, difficult as it may be, we may have no option.