ACTS 1.9: And when he had said these things, as they were looking on, he was lifted up, and a cloud took him out of their sight. (10) And while they were gazing into heaven as he went, behold, two men stood by them in white robes, (11) and said, “Men of Galilee, why do you stand looking into heaven? This Jesus, who was taken up from you into heaven, will come in the same way as you saw him go into heaven.” (ESV)
In Acts 1.3 Luke tells us that Jesus presented Himself alive to His disciples for 40 days. The Gospels record unique events during these 40 days of things Jesus did and said. All of them record that Jesus revealed Himself alive in His glorified body. And in the case of the event where Thomas got tagged with the expression, “doubting Thomas”, we learn that Jesus’ body bore the scars of the nail wounds in His hands and the spear wound in His side.
During these 40 days Jesus gave the Great Commission in the last verses of Matthew on a mountain in Galilee. Later, as the 40 days drew to a close, as recorded in Luke 24.44-53, Jesus set forth the Gospel message mandate for His disciples to be witnesses to Him, and witnesses that He was raised from the dead.
And in the same way that these verses in Acts describe the ascension of Jesus into heaven, they provide the information to the disciples that Jesus will come again in the same way He was taken into heaven. And this is in keeping with what Jesus said to the High Priest during His trial in Mark 14.62: “and you will see the Son of Man seated at the right hand of Power, and coming with the clouds of heaven.” (ESV) So Jesus is sitting at the right hand of power right now, and He will come again, descending from heaven to earth.
The time to have a right relationship with Jesus is now. There will not be a second chance after His coming. I believe Hebrews 9.28 supports this idea by saying, “so Christ, having been offered once to bear the sins of many, will appear a second time, not to deal with sin but to save those who are eagerly waiting for him.” (ESV)