Numbers 9:1-5

The LORD spoke to Moses in the Desert of Sinai in the first month of the second year after the Israelites left Egypt. He said, “Tell the Israelites to celebrate the Passover at the appointed time. That appointed time is the fourteenth day of this month at twilight; they must obey all the rules about it.” So Moses told the Israelites to celebrate the Passover, and they did; it was in the Desert of Sinai at twilight on the fourteenth day of the first month. The Israelites did everything just as the LORD commanded Moses.