Numbers 9:6-10

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.