And there were certain men, who were unclean by reason of the dead body of a man, so that they could not keep the passover on that day: and they came before Moses and before Aaron on that day: and those men said unto him, We are unclean by reason of the dead body of a man: wherefore are we kept back, that we may not offer the oblation of Jehovah in its appointed season among the children of Israel? And Moses said unto them, Stay ye, that I may hear what Jehovah will command concerning you. read more.
And Jehovah spake unto Moses, saying, Speak unto the children of Israel, saying, If any man of you or of your generations shall be unclean by reason of a dead body, or be on a journey afar off, yet he shall keep the passover unto Jehovah. In the second month on the fourteenth day at even they shall keep it; they shall eat it with unleavened bread and bitter herbs: they shall leave none of it unto the morning, nor break a bone thereof: according to all the statute of the passover they shall keep it.

For the king had taken counsel, and his princes, and all the assembly in Jerusalem, to keep the passover in the second month. For they could not keep it at that time, because the priests had not sanctified themselves in sufficient number, neither had the people gathered themselves together to Jerusalem. And the thing was right in the eyes of the king and of all the assembly.