And prepare yourselves,.... To do their work in this service of the sanctuary, the passover; that they be ready to do it, and diligent in it, and perform it according to the law of God: by the houses of your fathers, after your courses; such of them whose turn in course it was to officiate: according to the writing of David king of Israel, and according to the writing of Solomon his son; who had given in writing directions in what manner their courses should be observed, see Ch1 23:1.