2 Chronicles 23:2-6

2They went throughout Judah and gathered the Levites from all the cities of Judah and the leading patriarchs of Israel. They came to Jerusalem

3and the entire congregation made a covenant with the king in the House of God. Then he said to them: “Behold, the king’s son! He must reign as Adonai promised concerning David’s sons.

4This is what you should do: a third of you, kohanim and Levites coming on duty on Shabbat will keep watch at the gates,

5a third of you shall be in the royal palace, and a third at the Foundation Gate, and all the people shall be in the courtyard, and all the people should be in the courtyard of the House of Adonai.

6But let no one enter into the House of Adonai except the kohanim and the ministering Levites. They may come in, for they are kadosh, and let all the people observe the service of Adonai.