Charles Ellicott Commentary Leviticus 23:16

"even unto the morrow after the seventh sabbath shall ye number fifty days; and ye shall offer a new meal-offering unto Jehovah." — Leviticus 23:16 (ASV)

Even until the day after the seventh sabbath. —That is, the day after the seven complete weeks, or the fiftieth day. Therefore, its name is the “Pentecost, or fiftieth-day” feast in the New Testament (Acts 2:1; Acts 20:16; 1 Corinthians 16:8), and the “feast of weeks” in the Old Testament (Exodus 34:12; Deuteronomy 16:10; Deuteronomy 16:16; 2 Chronicles 8:13). The fiftieth day, according to the Jewish canons, may fall on the 5th, 6th, or 7th of Sivan, the third month of the year, i.e., from the new moon of May to the new moon of June.

Shall offer a new meat offering. —That is, it was an offering of the firstfruits of the wheat harvest, in contrast to the omer of firstfruits, which was from the barley harvest. For this reason, this festival is also called “the feast of harvest” (Exodus 23:16), because it concluded the harvest of the later grain.