Numbers 9:6-10

6However, there were some men who could not celebrate Passover because of being defiled by a dead body. So they came to Moses and Aaron on that same day,

7and these men said to him, “We have become unclean because of a dead man’s body. Why should we be kept from presenting the offering of Adonai at the appointed time with the rest of Bnei-Yisrael?”

8Moses answered them, “Wait, and I will inquire what Adonai commands concerning you.”

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.