'Keep Watch' in the Bible

He commanded them, saying, “This is the thing that you shall do: a third of you who come in [reporting for duty] on the Sabbath shall keep watch over the king’s house

(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.

Two parts of you, even all who go out on the sabbath, shall also keep watch over the house of the Lord for the king.