Bamidbar 9:3-5

Orthodox Jewish Bible

³ In the fourteenth day of this month, at twilight, ye shall observe it in its appointed season; according to kol chukkot of it, according to all the mishpatim thereof, shall ye observe it.

⁴ And Moshe spoke unto the Bnei Yisroel, that they should observe the Pesach.

⁵ And they observed the Pesach on the fourteenth day of the first month at twilight in the Midbar Sinai; according to all that Hashem commanded Moshe, so did the Bnei Yisroel.