Leviticus 23:9 And the LORD spake unto Moses, saying, Speak unto the children of Israel, and say unto them … ye shall bring a sheaf of the firstfruits of your harvest unto the priest: And he shall wave the sheaf before the LORD, to be accepted for you: on the morrow after the sabbath the priest shall wave it. …. it shall be a statute for ever throughout your generations in all your dwellings.
Numbers 28:26 Also in the day of the firstfruits, when ye bring a new meat offering unto the LORD, after your weeks be out, ye shall have an holy convocation; ye shall do no servile work:
1 Corinthians 15:20 But now is Christ risen from the dead, and become the firstfruits of them that slept.