Numbers 9:10-13

10“Say to the Israelites, ‘If any one of you or of your descendants becomes [ceremonially] unclean because of [touching] a dead body or is on a distant journey, he may, however, observe the Passover to the Lord.

11On the fourteenth day of the second month [thirty days later] at twilight, they shall observe it; they shall eat it with unleavened bread and bitter herbs.

12They shall leave none of it until morning nor break any of its bones; in accordance with all the statutes of the Passover they shall observe it.

13But the man who is [ceremonially] clean and is not on a journey, and yet does not observe the Passover, that person shall be cut off from among his people [excluding him from the atonement made for them] because he did not bring the Lord’s offering at its appointed time; that man will bear [the penalty of] his sin.