Numbers 9:4

²Speak, and let the children of Israel keep the Passover in its season.

³On the fourteenth day of the first month at even, thou shalt keep it in its season; thou shalt keep it according to its law, and according to its ordinance.

— Numbers 9:4 —

⁵on the fourteenth day of the first month in the wilderness of Sinai, as the Lord appointed Moses, so the children of Israel did.

⁶And there came men who were unclean by reason of a dead body, and they were not able to keep the Passover on that day; and they came before Moses and Aaron on that day.