Jesus appeared to his disciples over a period of forty days and spoke about the kingdom of God. (Acts 1:3)
The time between his resurrection and ascension was vitally important for Jesus. He could not sit back, basking in the victory of the moment. He couldn't take time out, visiting the family back in Nazareth. He didn't arrange a 'Resurrection' tour ('c0me and see the miracle man!') He focused himself on the next step of the great purpose for which he had come. Jesus had only forty days to spend on earth after being raised before he went to heaven. This was a pre-determined time, not a moment longer or shorter (the Old Testament makes that clear; study the various feasts and you'll discover he would ascend forty days after he rose again).
What did Jesus do during this inbetween time? He spoke to the disciples about the kingdom of God; that was his priority. Even when they tried to distract and divert him to their way of thinking by asking about restoring the natural kingdom of Israel (which shows they still hadn't understood), Jesus refused to enter into dialogue about secondary or peripheral matters. Nothing would distract him. He concentrated on the important, the vital, the essential. He didn't allocate to the disciples their ministries or titles. He didn't tell them to arrange or attend conferences or instruct them regarding their preaching schedules. His resurrection had launched the next phase of God's eternal purpose, and his ascension would be the prelude to the coming of the Holy Spirit at Pentecost. Jesus had far bigger fish to fry than indulging the whims and personal agendas of the disciples. It was time for them to get in on his plan - so he spoke to them about the kingdom of God.
Now that Easter is over and everybody is filled with chocolate and hot cross buns and sung their resurrection songs, for many the Church tends to slip back into its own sub resurrection existence in which people live as if Jesus were still in the grave or had never reached the Cross. The world carries on as if nothing of significance has happened. That is because we reduce the resurrection to an event we remember on the calendar instead of living in the power of the Jesus who is alive today and present in us through the Holy Spirit - as he is so are we in this world (1John 4:17). The Spirit who raised Jesus from the dead is living in us! (Romans 8:11). Let's not put Easter on the shelf as if it really makes no difference to the way we live. Jesus spent those forty days in intense focused activity in which he knew that he had that small window of time in which he would impart to these apostles their future destiny. He didn't waste it on the trivial things we so often see as the essential - his priority was the kingdom of God. That is why Jesus said: 'Seek first the kingdom of God and his righteousness - make the kingdom of God your priority' (Matthew 6:33).
Any priority that is not the kingdom of God is a complete waste of time and bears no relationship to the purpose of the resurrection of Jesus. I pray that we all focus on Jesus' priority - the kingdom of God.