In our first reading, St Luke records how, having seen the risen Jesus during forty days, the disciples saw him ascend. We might ask: 'Where was he during those forty days, when not with his disciples?' and 'Where is he now?' and 'Why did he have to go away?'
Today's Gospel answers the first question. It describes how on Easter Sunday evening, having eaten with his disciples, Jesus told them they would be his witnesses, and was carried up into heaven. During those forty days, therefore, Jesus was already in heaven, from where he returned, repeatedly, to speak to his disciples. Today's event was a powerful confirmation of the exalted status Jesus already possessed.
From St John we learn that Our Lord's Ascension had been urgent. He tells us how on Easter morning Mary Magdalen saw Jesus, and, when she clung to Him, he said, 'Do not hold me, for I have not yet ascended to my Father.' Jesus had left the tomb in his risen state, but had not yet left this universe. (There is a tradition that he had been with his mother.) Mary Magdalene could not delay Jesus from completing the departure his death had begun; instead she was sent off as the first preacher of Jesus' Ascension.
To where did Our Lord ascend? Not to outer space, as if we could reach him in a rocket. The authors of the Scriptures knew we must use imagery to express realities the human mind cannot comprehend. Jesus' body, crucified and raised, does not belong in this universe, but through it God's saving power - the Holy Spirit - enters this universe so that we may journey to glory, following Jesus. So St Paul pictures Jesus enthroned above all so as to fill all. The Letter to the Hebrews compares Him with the Jewish High Priest, who entered the inner sanctuary once a year: Jesus, in his humanity, has entered God's presence decisively, and as our 'trailblazer'.
The angels predicted Jesus' return in glory. Then his members will rise from the dead and share his exaltation. Jesus' body, which lives in a fuller way than before his death, is the 'prototype' of our fuller life - so that while Luke speaks of Jesus entering heaven, Jesus spoke of going to prepare a place for us. Until he returns to take us to be with him, Jesus' body does not belong in this universe: the space it occupies is not in continuity with ours, so that it is meaningless to ask where it is in relation to our own position.
Our third question was why Jesus had to depart, why his glorified body must not belong to this universe. First, his return must cut across the natural development of this universe and bring us an exaltation no natural power may achieve, so that our share in the divine bliss may be received as a gift - though it will be the fulfilment our humanity needs, and the fulfilment of the universe that has been our home.
Further, Jesus must not belong to this universe, because we must not belong. It is not our final home; our goal is to abide with Jesus 'in the Father's bosom', as John puts it. In a world marred by sin, we are 'resident aliens', and our journey means sharing in Jesus' dying and rising. He explained at the Last Supper that he must depart so that the Holy Spirit might come - as the Paraclete, the 'Friend for the campaign'. After his resurrection, as we heard, Jesus promised 'power from on high', a special coming of the Spirit fulfilled at Pentecost. It is not that Jesus' departure 'left space for' the Spirit; rather, his death and resurrection, his going to glory, are the channel of the Spirit's coming, and mean that the Spirit guides us in a way proper to pilgrims, makes us journey by faith and hope in the unseen Leader.
So it is for our greater glory that Jesus departed. The Holy Spirit, the divine Love who 'energised' Our Lord's ministry, makes us his witnesses. By dying on the cross, Jesus communicated God's mercy to a needy world; it is the privilege of his members, who share his mission, to be ourselves transparent to God the Father's kindness, and so, by love, lay hold on the divine goal Jesus has claimed for us.