Bible Verses About The Levites: Zeal against idolatry a cause of their appointment

Moshe stood at the entrance to the camp and shouted, "Whoever is for ADONAI, come to me!"All the descendants of Levi rallied around him.

He told them, "Here is what ADONAI, the God of Isra'el, says: 'Each of you, put his sword on his side; and go up and down the camp, from gate to gate; and every man is to kill his own kinsman, his own friend and his own neighbor!"

The sons of Levi did what Moshe said, and that day three thousand of the people died.