2 Chronicles 30:2-3

2, 3.

To keep the passover in the second month The law expressly allowed those to keep the passover in the second month who, for special reasons, were unable to keep it in the first. Those reasons were uncleanness by reason of a dead body, and absence on a journey afar off. See Numbers 9:10-11. At that time, that is, in the first month, both these reasons, virtually, prevented most of the nation from holding the passover, because the priests had not sanctified themselves sufficiently, neither had the people gathered themselves together to Jerusalem. So the priests were ceremonially unclean, and the people were absent.