by the words of the Lord
2 Chronicles 30:12
Also in Judah the hand of God was to give them one heart to do the commandment of the king and of the princes, by the word of the LORD.
to cleanse
1 Chronicles 23:28
Because their office was to wait on the sons of Aaron for the service of the house of the LORD, in the courts, and in the chambers, and in the purifying of all holy things, and the work of the service of the house of God;