What does the Bible say about the Holy Spirit's coming at Pentecost?

The coming of the Holy Spirit at Pentecost is a momentous event detailed in Acts 2, marking the beginning of the church's public ministry. Prior to this event, the Holy Spirit was present but had not come in the fullness of His power as He does after Christ's ascension. Jesus emphasized this necessity in John 7:39, stating that the Spirit 'was not yet given' because Jesus had not yet been glorified. Following His resurrection and ascension, the Spirit was poured out on the day of Pentecost, equipping the apostles to preach the gospel to every nation in languages they did not previously know, fulfilling the promise of God to empower His witnesses (Acts 1:8).