2 Chronicles 23:6

But let no one enter the house (temple) of the Lord except the priests and the Levites who minister; they may enter, for they are holy. And let all the people carefully observe the law of the Lord.

1 Chronicles 23:28-32

For their duty is to assist [the priests] the sons of Aaron in the service of the house of the Lord, in [caring for] the courtyards, the chambers, the purifying of all holy things, and any work of the service of the house of God,

2 Kings 11:6-7

(a third shall also be at the [city] gate Sur, and a third at the gate behind the guards); so you shall keep watch over the palace [from three posts] for defense.

Treasury of Scripture Knowledge

Summary

But let none come into the house of the LORD, save the priests, and they that minister of the Levites; they shall go in, for they are holy: but all the people shall keep the watch of the LORD.

They that minister

Bible References

They that minister

2 Kings 11:6
(a third shall also be at the [city] gate Sur, and a third at the gate behind the guards); so you shall keep watch over the palace [from three posts] for defense.
1 Chronicles 23:28
For their duty is to assist [the priests] the sons of Aaron in the service of the house of the Lord, in [caring for] the courtyards, the chambers, the purifying of all holy things, and any work of the service of the house of God,