Numbers 9:2-5

2Let the children of Israel also hold the passover at its set time;

3on the fourteenth day in this month between the two evenings, ye shall hold it at its set time; according to all the rites of it, and according to all the ordinances thereof shall ye hold it.

4And Moses spoke to the children of Israel, that they should hold the passover.

5And they held the passover in the first [month] on the fourteenth day of the month, between the two evenings, in the wilderness of Sinai: according to all that Jehovah had commanded Moses, so did the children of Israel.