Acts 1:9-11 ESV
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. And while they were gazing into heaven as he went, behold, two men stood by them in white robes, 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.”
This short passage leaves us face to face with two of the most difficult conceptions in the New Testament.
First, it tells of the Ascension. Only Luke tells this story and he has already related it in his gospel (Luke 24:50-53). For two reasons the Ascension was an absolute necessity.
One was that there had to be a final moment when Jesus went back to the glory which was his. The forty days of the resurrection appearances had passed. Clearly that was a time which was unique and could not go on forever. Equally clearly the end to that period had to be definite. There would have been something quite wrong if the resurrection appearances had just simply petered out.
For the second reason we must transport ourselves in imagination back to the time when this happened. Nowadays we do not regard heaven as some local place beyond the sky; we regard it as a state of blessedness when we will be forever with God. But every man, even the wisest, in those days thought of the earth as flat and of heaven as a place above the sky. Therefore, if Jesus was to give his followers unanswerable proof that he had returned to his glory, the Ascension was absolutely necessary.
But we must note this. When Luke tells of this in his gospel he says, “They returned to Jerusalem with great joy.” ( Luke 24:52 ). In spite of the Ascension, or maybe because of it, the disciples were quite sure that Jesus was not gone from them but that he was with them forever.
Second, this passage brings us face to face with the Second Coming. About the Second Coming we must remember two things.
First, to speculate when and how it will happen is both foolish and useless, Jesus said that not even he knew the day and the hour when the Son of Man would come ( Mark 13:32 ). There is something almost blasphemous in speculating about that which was hidden from even Christ himself.
Second, the essential teaching of Christianity is that God has a plan for man and the world. We are bound to believe that history is not a haphazard conglomeration of chance events which are going nowhere. We are bound to believe that there is some divine far off event to which the whole creation moves and that when that consummation comes Jesus Christ will be Judge and Lord of all. The Second Coming is not a matter for speculation and for illegitimate curiosity; it is a summons to make ourselves ready for that day when it comes.