Numbers 9:6-11

6But some of the men had been ceremonially defiled by touching a dead body, so they could not celebrate the Passover that day. They came to Moses and Aaron that day

7and said, “We have become ceremonially unclean by touching a dead body. But why should we be prevented from presenting the Lord’s offering at the proper time with the rest of the Israelites?”

8Moses answered, “Wait here until I have received instructions for you from the Lord.”

9This was the Lord’s reply to Moses.

10“Give the following instructions to the people of Israel: If any of the people now or in future generations are ceremonially unclean at Passover time because of touching a dead body, or if they are on a journey and cannot be present at the ceremony, they may still celebrate the Lord’s Passover.

11They must offer the Passover sacrifice one month later, at twilight on the fourteenth day of the second month. They must eat the Passover lamb at that time with bitter salad greens and bread made without yeast.