Numbers 28:15-19

And one kid of the goats for a sin offering unto the LORD shall be offered, beside the continual burnt offering, and his drink offering.

And in the fourteenth day of the first month is the passover of the LORD.

And in the fifteenth day of this month is the feast: seven days shall unleavened bread be eaten.

In the first day shall be an holy convocation; ye shall do no manner of servile work therein:

But ye shall offer a sacrifice made by fire for a burnt offering unto the LORD; two young bullocks, and one ram, and seven lambs of the first year: they shall be unto you without blemish: