Prepare your brethren ... - i. e. “as you minister to your brethren the people, by killing and flaying their offerings and handing the blood to the priests, instruct them how they are to eat the Passover acceptably.” It is implied that many would be ignorant of the requirements of the Law.
Related Commentaries of 2 Chronicles 35:6
2 Chronicles 35:6
6 So kill the passover, and sanctify yourselves, and prepare your brethren, that they may do according to the word of the LORD by the hand of Moses.