Pentecost is a word that comes from the Greek word pentekoste, which means "fiftieth." It refers to a festival celebrated on the 50th day after Passover. In the Old Testament, this festival is called Shavu'oth, or the Feast of Weeks (Exodus 34:22; Deuteronomy 16:10). It is called the Feast of Weeks because it takes place seven weeks after Passover. Other names for this festival include:
The Feast of Harvest, because of its relationship with harvest season (Exodus 23:16).
The Day of Firstfruits, because two loaves of freshly ground grain were given to God (Numbers 28:26). (This name should not be confused with the offering of firstfruits at the beginning of the harvest season, mentioned in Leviticus 23:9–14.)
The Feast of Weeks was one of three pilgrimage festivals in the Old Testament. People had to appear before God with gifts and offerings (Exodus 23:14–17). It was mainly a harvest celebration, marking the end of the barley harvest and the start of the wheat harvest. Traditionally, grain harvest lasted from Passover, when the first grain was cut (Deuteronomy 16:9). It ended at Pentecost, which marked its end in mid-June. The Jewish historian Josephus said to Pentecost was called "closing" because it closed the harvest season (Antiquities 3.10.6).
Each year, the priest waved a sheaf of newly harvested grain before God. He did this the day after the Sabbath during the Festival of Unleavened Bread, which is the seven days after Passover. Then the people counted 50 days from this offering until the day after the seventh Sabbath to celebrate the Feast of Weeks (Leviticus 23:11). On this day, two loaves of bread made from two-tenths of an ephah of flour and baked with yeast were waved before the Lord (Leviticus 23:17). Freewill offerings were encouraged (Deuteronomy 16:10). It was a time of great celebration, and no work was to be done (Leviticus 23:21; Deuteronomy 16:11). The Feast of Weeks in Solomon’s time is mentioned in 2 Chronicles 8:13, the only reference to it outside of the Pentateuch in the Old Testament. Ezekiel does not mention it in his calendar for future festivals (Ezekiel 45–46).
The New Testament first mentions Pentecost as the day the Holy Spirit was poured out on the followers of Jesus. Many Bible teachers understand this event as marking the beginning of the church (Acts 2:1). Since Pentecost was a required festival, Jewish people gathered from far away to observe it in Jerusalem. This made it a good time for God's work to reach many people. Paul also refers to Pentecost twice when planning his travels. He mentions delaying his visit to the Corinthians until after Pentecost (1 Corinthians 16:8). Later, he wanted to arrive in Jerusalem in time for Pentecost (Acts 20:16).