Numbers 9:9-12

9Then Adonai spoke to Moses saying,

10“Say to Bnei-Yisrael saying: If any man, whether you or your descendants, becomes unclean because of a dead body, or is away on a long journey, he may yet observe Adonai’s Passover.

11They are to celebrate it at twilight on the fourteenth day of the second month. With matzot and bitter herbs they are to eat it.

12They are not to leave any of it until morning, or break any bones. When they celebrate Passover they are to observe all its regulations.