Numbers 9:1
And the LORD 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, And the LORD 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,
The verse resumes the narrative of Israel's journey left at Sinai in Exodus, with Israel still encamped at Sinai in the wilderness of Sinai, and turns to its experiences on the journey toward Kadesh-barnea. It dates the Lord speaking to Moses to the first month of the second year after coming out of the land of Egypt. This was when the tabernacle was first located in the wilderness of Sinai. Israel had remained at Horeb for nearly or quite a year and did not leave until the latter part of the second month of that year.
The word then spoken commanded the people to keep the Passover again at Sinai in the first month of the second year, which they did as the second Passover. All the feasts given to Israel occurred annually and were to be observed only when due. The one exception was that those unable to keep the Passover in the first month because of defilement and ceremonial uncleanness were to keep it on the fourteenth day of the second month, on the same day of the month in the second month.
This was the only Passover observance in the wilderness. The Passover was then omitted until the people entered Canaan. Shortly after this observance Israel refused to enter the land of Canaan, and the Lord declared that all that generation would die in the wilderness except Joshua the son of Nun and Caleb the son of Jephunneh.