“And both the singers and the porters kept the ward of their God, and the ward of the purification, according to the commandement of Dauid, and of Solomon his sonne.”
1611 King James Version (KJV)
12:45 The ward - That ward, or charge, which God had prescribed to 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.