Leviticus 23:5-11

5In the first month, on the fourteenth day of the month at even, is Jehovah’s passover. 6And on the fifteenth day of the same month is the feast of unleavened bread unto Jehovah: seven days ye shall eat unleavened bread. 7In the first day ye shall have a holy convocation: ye shall do no servile work. 8But ye shall offer an offering made by fire unto Jehovah seven days: in the seventh day is a holy convocation; ye shall do no servile work.

9And Jehovah spake unto Moses, saying, 10Speak unto the children of Israel, and say unto them, When ye are come into the land which I give unto you, and shall reap the harvest thereof, then ye shall bring the sheaf of the first-fruits of your harvest unto the priest: 11and he shall wave the sheaf before Jehovah, to be accepted for you: on the morrow after the sabbath the priest shall wave it.