Nehemiah 13:22
22 Then I commanded the Levites tthat they should purify themselves and come and guard the gates, to keep the Sabbath day holy. uRemember this also in my favor, O my God, and spare me according to the greatness of your steadfast love.
Nehemiah 13:30
30 iThus I cleansed them from everything foreign, and I established the duties of the priests and Levites, each in his work;