Numbers 9:5-7

American Standard Version

⁵ And they kept the passover in the first month, on the fourteenth day of the month, ^[a]at even, in the wilderness of Sinai: according to all that Jehovah commanded Moses, so did the children of Israel. ⁶ And there were certain men, who were unclean by reason of the dead body of a man, so that they could not keep the passover on that day: and they came before Moses and before Aaron on that day: ⁷ and those men said unto him, We are unclean by reason of the dead body of a man: wherefore are we kept back, that we may not offer the oblation of Jehovah in its appointed season among the children of Israel?