C. S. Lewis wrote concerning the ascension of Jesus:
We...tend to slur over the risen manhood of Jesus, to conceive Him, after death, simply returning into Deity, so that the Resurrection would be no more than the reversal or undoing of the Incarnation" (Miracles, p. 151, quoted on p. 5 in Jesus Ascended by Gerrit Scott Dawson, T&T Clark, 2004).
Following on Lewis' thought,
Gerrit Scott Dawson warns of...
...enormous theological problems raised by disembodying Christ's ascension. For instance, if Jesus slipped out of his human body, who is sitting at God's right hand? Is it Jesus, whose voice the disciples heard, whose touch they felt...or is it the eternal Son of God, who once knew what it was like to be a man but is no longer bone of our bone and flesh of our flesh? If the latter, what effect would a bodiless Christ have on the future work affirmed in the [Nicene] Creed, his coming again and his judgement of the living and dead? To put it bluntly, if Jesus did not go up as a man, he cannot come again as a man. The Judge would not be our Brother, not the one tempted in all ways as we are, not the man with the nail-scarred hands and the 'rich wounds yet visible above'. He might be God in that case, but he would not be human. And we would be lost (p. 5).
As Dawson goes on to note...
...Our salvation depends on [Jesus'] continuing union with us. If the Son of God came to us where we are, but then left us, if he went away and did not take us with him, we would still be lost. In fact, we could then begin a whole new series of books entitled Left Behind, though with a decidedly gloomier slant! For any view of the ascension as Jesus slipping off his humanity is a sentence of condemnation. We cannot be united to him in the Holy Spirit if he is no longer flesh or our flesh and bone of our bone...If he dropped the hypostatic union with humanity, then he dropped us, and we are left forsaken on this side of the great divide, unable to fulfill our purpose, find forgiveness and restored communion, or enact our mission (p. 6).
But the good news is that Jesus has indeed arisen clothed in our humanity! Dawson notes:
The incarnation continues, and so we are included in the life of God. That is the essential meaning of the ascension. We are not left alone. Jesus has gone before us in a way we may follow through the Holy Spirit whom he has sent, because the way is in his flesh, in his humanity. Jesus is himself that new and living way (p. 7).
May your celebration of Jesus' ascension bring you great joy and assurance!