Nehemiah 12:45

Both the singers and the porters kept the ward of their God That ward or charge which God had prescribed them. And, in particular, the charge of purification, of taking care that no unclean person or thing should enter into the house or courts of the Lord. Or, the meaning may be, the singers sung orderly in their courses, as they were appointed, and thereby kept the ward of their God; and the porters kept the ward of the purification, that is, duly observed the orders about it, in preventing the temple from being defiled by any unclean person or thing. According to the commandment of David and of Solomon his son Who had regulated all things belonging to the duty of these persons.