How do we know the Holy Spirit was sent after Jesus' ascension?

The historical event of Pentecost in Acts 2 demonstrates the sending of the Holy Spirit following Jesus' ascension to glory. It occurred fifty days after the resurrection, during which Jesus assured His disciples of this promise. The ten days between His ascension and the coming of the Spirit allowed the disciples to prepare through prayer, demonstrating their readiness to receive this incredible gift. This act not only symbolizes the fulfillment of Christ's promise but also the initiation of the Church's mission empowered by the Spirit's presence and power, affirming the truth of Scripture regarding the timing and purpose of the Holy Spirit’s coming.