1-3. While Israel was camped at Shittim (Acacia Grove), the men began to have sex with the Moabite women. It started when the women invited the men to their sex-and-religion worship. They ate together and then worshiped their gods. Israel ended up joining in the worship of the Baal of Peor. God was furious, his anger blazing out against Israel.
10-13. God spoke to Moses: “Phinehas son of Eleazar, son of Aaron the priest, has stopped my anger against the People of Israel. Because he was as zealous for my honor as I myself am, I didn’t kill all the People of Israel in my zeal. So tell him that I am making a Covenant-of-Peace with him. He and his descendants are joined in a covenant of eternal priesthood, because he was zealous for his God and made atonement for the People of Israel.”