Numbers 25:4-8

And the Lord said to Moses, “Take all the leaders of the people and execute them in broad daylight before the Lord, so that the fierce anger of the Lord may turn away from Israel.”

So Moses said to the judges of Israel, “Each of you kill his men who have become followers of Baal of Peor.”

Then behold, one of the sons of Israel came and brought to his relatives a Midianite woman, in the sight of Moses and in the sight of the whole congregation of the sons of Israel, while they were weeping at the entrance of the tent of meeting.

When Phinehas the son of Eleazar, the son of Aaron the priest, saw it, he rose up from the midst of the congregation and took a spear in his hand,

and he went after the man of Israel into the inner room of the tent and pierced both of them, the man of Israel and the woman, through the abdomen. So the plague on the sons of Israel was brought to a halt.