Numbers 9:9-12

9Then the LORD said to Moses, 10“Tell the Israelites: ‘When any one of you or your descendants is unclean because of a dead body, or is away on a journey, he may still observe the Passover to the LORD. 11Such people are to observe it at twilight on the fourteenth day of the second month. They are to eat the lamb, together with unleavened bread and bitter herbs; 12they may not leave any of it until morning or break any of its bones. They must observe the Passover according to all its statutes.