Numbers 9:4

1 And Jehovah spake unto Moses in the wilderness of Sinai, in the first month of the second year after they were come out of the land of Egypt, saying,

2 Moreover let the children of Israel keep the passover in its appointed season.

3 In the fourteenth day of this month, at even, ye shall keep it in its appointed season: according to all the statutes of it, and according to all the ordinances thereof, shall ye keep it.

4 And Moses spake unto the children of Israel, that they should keep the passover.

5 And they kept the passover in the first month, on the fourteenth day of the month, 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?