Summary: It is the greatest story ever told. And now, the great story of God's faithfulness and justice and mercy, is being entrusted to the witnesses, to Christ's disciples, to proclaim to the world.
So imagine you're walking down the street, minding your own business when you happen upon a large crowd. You notice that all faces are turned upwards toward the sky. You follow the gazes of the crowd and see above you a massive cloud with a pair of feet showing just below the bottom edge of the cloud. It's too strange a sight to just continue on your way. So you stop and stare upwards with the rest of the ever-growing crowd. All around you, people begin to mumble. There must be some logical explanation for this; maybe the guy is hanging from a hot air balloon that can't be seen because of the cloud, or perhaps he's hang gliding. Whatever the cause, it's like a train wreck, and you just can't stop looking, you stand transfixed with many others, wondering what on earth is going on.
There is a tradition in art that shows just such a scene, only 2,000 years ago. It depicts the disciples gathered on a hilltop, straining their faces upward. Above them is a cloud with a pair of feet just showing beneath it. Of course, the painting is of the ascension of Jesus Christ, but the disciples are noticeably amazed. Despite three years of watching Jesus perform miracle after miracle, the painting shows the disciples noticeably transfixed by the wonder of this strange sight. To witness such a sight would indeed be most unusual. We may try to puzzle about what "really happened" and offer some reasonable explanation. In the present day, we wonder exactly what Luke might have been trying to describe when he said Jesus "left them and was taken up to heaven." Where did he really go? What did the disciples actually witness?
These are the questions that surely run through our mind as we ponder Christ's ascension. In the wake of such a phenomenal event, it would be easy to stand around with the others who saw a man miraculously lifted into the sky, or perhaps only caught sight of his feet hanging just below a cloud. But to do so would miss the point of the ascension itself. Here at the close of his ministry on earth, Jesus is focused on helping believers understand his life and ministry, death and resurrection, and the scope of God's saving love. And these moments surrounding Christ's ascension are meant to open our eyes to see the power of God's love that takes the worst the world can do and transforms it into a witness to God's redemptive love and power.
The ascension is about understanding the depths of God's mercy. Throughout Luke's gospel, the disciples have had difficulty understanding how Jesus fits into God's overall plan. But now, Luke tells us that Jesus "opened their minds so they could understand the Scriptures." And Jesus reminds them of all he has told them about his connection to the Law of Moses, the Prophets, and Psalms. So Jesus puts the pieces together in a compelling way so that their eyes are opened and they recognize him, not only as the risen manifestation of the teacher they have followed, but as the risen Lord, the son of the living God. Now they can see more fully that God is actively at work redeeming all of creation. And then Jesus says, "This is what is written: The Christ will suffer and rise from the dead on the third day, and repentance and forgiveness of sins will be preached in his name to all nations, beginning at Jerusalem." God's story, told in all of Scripture, continues through Jesus, and continues yet again in the work of the disciples. The disciples, each of us, have to understand fully the depth of God's love for the world, and then we have to see that we have a role in sharing the message of God's mercy in the world. Knowing that he was about to leave, Christ opened the minds of his followers; they were witnesses of all that he embodied. And being a witness, as the disciples were already discovering, was a big deal!