Charles Ellicott Commentary 2 Chronicles 35:6

"And kill the passover, and sanctify yourselves, and prepare for your brethren, to do according to the word of Jehovah by Moses." — 2 Chronicles 35:6 (ASV)

And sanctify yourselves. —Probably by washing the hands before handing the blood of sprinkling to the priests. (See 2 Chronicles 30:16 and following)

Prepare your brethren. —Prepare (the passover) for your brethren of the laity.

That they may do. — So as to do. The Levites themselves are to obey the prescriptions of the Mosaic Law.