Numbers 9:1-6 (NKJV)
[1] Now the Lord spoke to Moses in the Wilderness of Sinai, in the first month of the second year after they had come out of the land of Egypt, saying:
[2] “Let the children of Israel keep the Passover at its appointed time. [3] On the fourteenth day of this month, at twilight, you shall keep it at its appointed time. According to all its rites and ceremonies you shall keep it.”
[4] So Moses told the children of Israel that they should keep the Passover.
[5] And they kept the Passover on the fourteenth day of the first month, at twilight, in the Wilderness of Sinai; according to all that the Lord commanded Moses, so the children of Israel did.
[6] Now there were certain men who were defiled by a human corpse, so that they could not keep the Passover on that day; and they came before Moses and Aaron that day.
Numbers 9:14(NKJV)
[14] And if a stranger dwells among you, and would keep the Lord’s Passover, he must do so according to the rite of the Passover and according to its ceremony; you shall have one ordinance, both for the stranger and the native of the land.”