So Moses told the Israelites to celebrate the Passover,
Then Moses called all the elders of Israel together and told them, “Get the animals for your families and kill the lamb for the Passover.
That appointed time is the fourteenth day of this month at twilight; they must obey all the rules about it.”
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.