Numbers 9:6, 10

But 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

“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.