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

So Moses stood at the entrance to the camp and said, “Whoever is for the LORD, come to me.” And all the Levites gathered around him.

He told them, “This is what the LORD, the God of Israel, says: ‘Each of you men is to fasten his sword to his side, go back and forth through the camp from gate to gate, and slay his brother, his friend, and his neighbor.’”

The Levites did as Moses commanded, and that day about three thousand of the people fell dead.