Leviticus 23:15
And ye shall count to you from the morrow after the Sabbath, from the day that ye brought the sheaf of the wave-offering, there shall be complete seven Sabbaths.
Exodus 34:22
And thou shall observe the feast of weeks, [even] of the first-fruits of wheat harvest, and the feast of ingathering at the year's end.
Leviticus 23:10-11
Speak to the sons of Israel, and say to them, When ye have come into the land which I give to you, and shall reap the harvest of it, then ye shall bring the sheaf of the first-fruits of your harvest to the priest.
Leviticus 25:8
And thou shall number seven Sabbaths of years to thee, seven times seven years, and there shall be to thee the days of seven Sabbaths of years, even forty-nine years.
Deuteronomy 16:9-10
Thou shall number to thee seven weeks. From the time thou begin to put the sickle to the standing grain thou shall begin to number seven weeks.
Numbers 28:26
Also in the day of the first-fruits, when ye offer a new meal-offering to LORD in your [feast of] weeks, ye shall have a holy convocation. Ye shall do no servile work.