Pentecost: Institution of
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Exodus 23:16
You are also to keep the Feast of Harvest with the firstfruits of the produce from what you sow in the field. And keep the Feast of Ingathering at the end of the year, when you gather your produce from the field.
Exodus 34:22
And you are to celebrate the Feast of Weeks with the firstfruits of the wheat harvest, and the Feast of Ingathering at the turn of the year.
Leviticus 23:15–21
From the day after the Sabbath, the day you brought the sheaf of the wave offering, you are to count off seven full weeks. / You shall count off fifty days until the day after the seventh Sabbath, and then present an offering of new grain to the LORD. / Bring two loaves of bread from your dwellings as a wave offering, each made from two-tenths of an ephah of fine flour, baked with leaven, as the firstfruits to the LORD.
Numbers 28:26–31
On the day of firstfruits, when you present an offering of new grain to the LORD during the Feast of Weeks, you are to hold a sacred assembly; you must not do any regular work. / Present a burnt offering of two young bulls, one ram, and seven male lambs a year old as a pleasing aroma to the LORD, / together with their grain offerings of fine flour mixed with oil—three-tenths of an ephah with each bull, two-tenths of an ephah with the ram,
Deuteronomy 16:9–12, 16
You are to count off seven weeks from the time you first put the sickle to the standing grain. / And you shall celebrate the Feast of Weeks to the LORD your God with a freewill offering that you give in proportion to how the LORD your God has blessed you, / and you shall rejoice before the LORD your God in the place He will choose as a dwelling for His Name—you, your sons and daughters, your menservants and maidservants, and the Levite within your gates, as well as the foreigner, the fatherless, and the widows among you.