Charles Ellicott Commentary Nehemiah 12:45

"And they kept the charge of their God, and the charge of the purification, and [so did] the singers and the porters, according to the commandment of David, and of Solomon his son." — Nehemiah 12:45 (ASV)

Kept the ward. —This should be read differently. The priests and Levites kept the ward of their God, and the ward of purification, and the singers and porters, etc. To “keep the ward” is to observe the regular times and seasons of sacrifice and thanksgiving.