Numbers 9:3-5

VIN(i) 3 On the fourteenth day of this month, at twilight at its appointed time, you shall observe it. Keep it according to all its decrees and laws. 4 So Moses told the Israelites to celebrate the Passover. 5 They celebrated it on the fourteenth day of the first month at dusk while they were in the Desert of Sinai. The Israelites did everything as the LORD commanded Moses.