Exodus 12:18, 21
Exodus 12:18 NASB1995
In the first month, on the fourteenth day of the month at evening, you shall eat unleavened bread, until the twenty-first day of the month at evening.
Exodus 12:21 NASB1995
Then Moses called for all the elders of Israel and said to them, “Go and take for yourselves lambs according to your families, and slay the Passover lamb.