2 Chronicles 35:4

“And prepare yourselves, etc.] 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 <132301>1 Chronicles 23:124:31).”

“prepare yourselves by the houses of your fathers, after your courses--Each course or division was to be composed of those who belonged to the same fathers' house. according to the writing of David and . . . Solomon--Their injunctions are recorded (Ch2 8:14; 1Ch. 23:1-26:32).”

“35:4-6 The assignments of the priests and Levites mirrored the directions of David and Solomon (8:14-15; 1 Chr 24–26). The Passover animal was typically slaughtered by the offerer (Deut 16:5-6). However, because the offerers did not have time to purify themselves, Josiah continued the practice Hezekiah had begun of having the Levites slaughter the Passover animals (see 2 Chr 30:13-20). In Josiah’s time, the large number of participants also might have caused logistical problems.”

“the houses: 1Chr. 9:10-34; Neh 11:10-20 after your courses: The regulations formed by David, and established by Solomon, concerning the courses of the priests and Levites, were committed to writing, and preserved, for them to refer to continually. Josiah, as well as Hezekiah, required the priests and Levites to attend to their several duties, and encouraged them therein, but he neither added, altered, not retrenched anything. he merely enforced what had been established in the law, and in the regulations made by David and the contemporary prophets: "the commandment of the king....was by the word of the Lord." 1Chr. 23:1-26:32 and according: Ch2 8:14 2 Chronicles 35:5”