Jesus had made his real farewell to his disciples at the Last Supper, as recorded in the discourses of St John (John 13:31, 14-17). When Jesus left them after forty days, they were not full of grief and hopelessness, as they had been after the crucifixion. Instead, we are told that they returned to Jerusalem full of joy. The Risen Lord had promised to be with them always: ”...And remember I am with you always, to the end of the age” (Matt. 28:20).
What Luke seems to be doing in both Acts 1:1-11 and Luke 24:46-53 is to dramatise Jesus’ return to the Father. Cloud is often used in the bible as an image of God’s presence. The great prophet Elijah ascended into Heaven in a fiery chariot (2 Kings 2:11-12). The question of the angels - “Why are you men of Galilee standing here looking into the sky?” - might also be applied to us. Jesus is not remote like the gods of Olympus, but present among us all the time in our brothers and sisters and most especially in the Eucharist.
It is interesting that the disciples still thought that the Lord’s mission was to restore the kingdom to Israel. The Holy Spirit would lead them in a very different direction. The people whom God had chosen as his own, now had to preach his message throughout the world; and no one would be excluded from his love.