The Waiting and Learning
Acts 1 gives us an account of Jesus' telling his disciples to wait in Jerusalem "for the promise of The Father." But this waiting is not simply doing nothing. Jesus spends 40 days with them.
In these 40 days Jesus is a present companion and shows many proofs of his being alive. This was not vision or some apparition; this was a living breathing person. But Jesus also invests time with these followers in giving them some content by speaking of The Kingdom of God.
What is important to see about this time of waiting for "the promise of The Father" is that Jesus gives attention to one subject. This subject Jesus speaks about is to The Kingdom of God. The Kingdom of God was surely the content of Jesus' earthly ministry (parables). And here he continues to teach and speak of this important subject.
What is the connection here with The Holy Spirit and The Kingdom of God? It must be that Jesus is speaking and teaching about the Kingdom of God as a spiritual reality for all nations and not only the Jewish nation. The Holy Spirit would be/is the presence that creates all the nations as one in this spiritual Kingdom. This kind of Kingdom will be understood as it expands into all the world in the power of The Holy Spirit (Acts 1:8)
REFLECT: How do you understand the Kingdom of God as a spiritual reality enabled by The Holy Spirit? What kind of priority does The Kingdom of God occupy in you understanding of The Spirit's work to create a people of God?