Jamieson, Fausset and Brown on 2 Chronicles 35:6

6. So kill the passover, &c.--The design of the minute directions given here was to facilitate the distribution of the paschal lambs. These were to be eaten by the respective families according to their numbers (Ex 12:3). But multitudes of the people, especially those from Israel, having been reduced to poverty through the Assyrian devastations, were to be provided with the means of commemorating the passover. Therefore, the king enjoined the Levites that when the paschal lambs were brought to them to be killed (2Ch 35:7-9) they should take care to have everything put in so orderly a train, that the lambs, after due presentation, might be easily delivered to the various families to be roasted and eaten by themselves apart.