What happened changed everything for the Disciples?
The disciples were with Jesus for three years, had witnessed His miracles, watched His crucifixion, experienced His resurrection and even after all of that they had no clue that Jesus was investing everything He had done into them and sending them out to minister and share the gospel to all the world. In fact even after the resurrection they were still hiding out in and upper room and were asking Jesus when He was going to restore Israel. But something happened…something that would transform these men into world changers who preached the gospel everywhere they could. What was it? The Ascension and the day of Pentecost.
When the disciples had gathered in Bethany with Jesus they witnessed Him being raised up into Heaven before their eyes. It was at this moment that their eyes were opened and they understood that Jesus was not just some provincial ruler, but that He was the ruler of the universe, the cosmos. He was the King of King and the Lord of Lords. When they saw this they immediately worshipped Jesus right on the spot and they spent the next ten days praying God in the Temple. It was so profound that they went from hiding in a room to praising God in the most public of places. They saw who Jesus was and all of the pieces of the puzzle began to come together. It changed everything.
While praising the Lord the Holy Spirit descended into the room where they were gathered and filled them with power. While most focus on these events as a proof text for speaking in tongues or the manifestation of spiritual gifts, it is so much more. You see when the Holy Spirit descended on the believers they instantly went out into the streets and began to minister to everyone gathered there. In fact they began to preach the gospel of Jesus Christ for the first time, boldly and guess what happened? Three Thousand were immediately converted. The Holy Spirit empowered the believers to reach out and share the good news of salvation. They became activated. It changed everything.