Then Moses stood in the gate of the camp. — The third and crowning step was now to be taken. Though the idol had been seized and its destruction commenced, though Aaron had been rebuked and put to shame, yet the revel continued. Once launched on an evil course, the bulk of the people persisted in it. Moses felt that God was openly insulted by such conduct, against which death was denounced by the Law (Exodus 22:20), and which might at any moment provoke God to destroy the whole people (Exodus 32:10). He therefore proceeded to suppress the idolatry by a stern act of judicial severity — an execution on a large scale of those taken flagrante delicto. Standing in the gate — i.e., the principal gate — of the camp, he summoned to his aid those who were on the Lord’s side, and gave them orders to go through the camp from end to end, and put to death all whom they found still engaged in the mad revel.
All the sons of Levi. — This must not be understood literally. All the Levites would not have heard the summons of Moses, and some were evidently among those who persisted in idolatry (Exodus 32:27-29). In the language of the sacred writers, “all” constantly means “the greater part.”