Pinchas' act of zealotry in Numbers chapter 25 earns him the priesthood. But it also casts new light on a prior scene involving his tribe of Levi and the tribe of Shimon back in Genesis chapter 34.
"Pinchas son of Eleazar son of Aaron the priest has calmed my anger," God tells Moses. "Through his violent and vengeful zealotry, he has saved the Children of Israel. For this I give him my covenant of peace. And for endless days will he be a priest."