54 And Moses said to Korah: “Hear me, you sons of Levi: Is this a small thing unto you, that God has separated you from the congregation of Israel, and brought you near to Himself, to minister the service of the Tabernacle of the Lord.” And farther on, “Seek the priesthood also, so that you and all your congregation are gathered against the Lord. And what is Aaron that you murmur about him?”
Source: Letters (New Advent)