Exodus 23:16

Thou shalt not delay to offer the first of thy ripe fruits, and of thy liquors: the firstborn of thy sons shalt thou give unto me.

And thou shalt observe the feast of weeks, of the firstfruits of wheat harvest, and the feast of ingathering at the year's end.

And the LORD spake unto Moses, saying, Speak unto the children of Israel, and say unto them, When ye be come into the land which I give unto you, and shall reap the harvest thereof, then 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. And ye shall offer that day when ye wave the sheaf an he lamb without blemish of the first year for a burnt offering unto the LORD. And the meat offering thereof shall be two tenth deals of fine flour mingled with oil, an offering made by fire unto the LORD for a sweet savor: and the drink offering thereof shall be of wine, the fourth part of an hin. And ye shall eat neither bread, nor parched corn, nor green ears, until the selfsame day that ye have brought an offering unto your God: it shall be a statute for ever throughout your generations in all your dwellings. And ye shall count unto you from the morrow after the sabbath, from the day that ye brought the sheaf of the wave offering; seven sabbaths shall be complete: Even unto the morrow after the seventh sabbath shall ye number fifty days; and ye shall offer a new meat offering unto the LORD. Ye shall bring out of your habitations two wave loaves of two tenth deals; they shall be of fine flour; they shall be baked with leaven; they are the firstfruits unto the LORD. And ye shall offer with the bread seven lambs without blemish of the first year, and one young bullock, and two rams: they shall be for a burnt offering unto the LORD, with their meat offering, and their drink offerings, even an offering made by fire, of sweet savor unto the LORD. Then ye shall sacrifice one kid of the goats for a sin offering, and two lambs of the first year for a sacrifice of peace offerings. And the priest shall wave them with the bread of the firstfruits for a wave offering before the LORD, with the two lambs: they shall be holy to the LORD for the priest. And ye shall proclaim on the selfsame day, that it may be an holy convocation unto you: ye shall do no servile work therein: it shall be a statute for ever in all your dwellings throughout your generations.

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: But ye shall offer the burnt offering for a sweet savor unto the LORD; two young bullocks, one ram, seven lambs of the first year; And their meat offering of flour mingled with oil, three tenth deals unto one bullock, two tenth deals unto one ram, A several tenth deal unto one lamb, throughout the seven lambs; And one kid of the goats, to make an atonement for you. Ye shall offer them beside the continual burnt offering, and his meat offering, (they shall be unto you without blemish) and their drink offerings.

Seven weeks shalt thou number unto thee: begin to number the seven weeks from such time as thou beginnest to put the sickle to the corn. And thou shalt keep the feast of weeks unto the LORD thy God with a tribute of a freewill offering of thine hand, which thou shalt give unto the LORD thy God, according as the LORD thy God hath blessed thee: And thou shalt rejoice before the LORD thy God, thou, and thy son, and thy daughter, and thy manservant, and thy maidservant, and the Levite that is within thy gates, and the stranger, and the fatherless, and the widow, that are among you, in the place which the LORD thy God hath chosen to place his name there. And thou shalt remember that thou wast a bondman in Egypt: and thou shalt observe and do these statutes.

And when the day of Pentecost was fully come, they were all with one accord in one place.