Thematic Bible: Passover first commemorated

Yahweh spoke to Moses in the desert of Sinai, in the second year after they came out from the land of Egypt, in the first month, saying, "Let the {Israelites} observe the Passover at its appointed time. On the fourteenth day of this month {at twilight} you will perform it at its appointed time according to all its decrees; and according to all its stipulations you will observe it." read more.
So Moses spoke to the {Israelites} to observe the Passover. And they observed the Passover on the fourteenth day of the month {at twilight} in the desert of Sinai. According to all that Yahweh commanded Moses, thus the {Israelites} did.