Numbers 25:1, 6-8

When Israel lived in Shittim, the people began to commit sexual immorality with the daughters of Moab.

Just then one of the Israelites came and brought to his brothers a Midianite woman in the plain view of Moses and of the whole community of the Israelites, while they were weeping at the entrance of the tent of meeting. When Phinehas son of Eleazar, the son of Aaron the priest, saw it, he got up from among the assembly, took a javelin in his hand, and went after the Israelite man into the tent and thrust through the Israelite man and into the woman’s abdomen. So the plague was stopped from the Israelites.