and speaking about the kingdom of God-Acts 1:3b
The kingdom of God is never explicitly defined in the Bible. Yet, the Bible testifies to much of what the kingdom of God is, how the kingdom of God would come, and even of what the kingdom of God would look like-at least to some extent. In His earthly ministry Jesus spoke more about the kingdom than He spoke of any other single subject. For instance, in Luke 17:21 Jesus taught that the kingdom of God is within His people and not so much outside of His people. That is to say, God’s kingdom work is primarily wrought through the hearts and lives of His people by the power of the Holy Spirit. This internal work inside of His people over time has lasting effects upon the rest of the world that is fallen in sin. As the Holy Spirit transforms lives through the Gospel of the kingdom, the world becomes more like the kingdom of Christ (Revelation 11:15) . The kingdom would not come in ways observable as many thought. Jesus taught that His kingdom is not of this world (John 18:36) and that the kingdom is more valuable than treasure hidden in a field (Matthew 13:44) . He taught that the righteous will shine in the kingdom of heaven (Matthew 14:43) and that the kingdom is like a mustard seed (Matthew 13:31,32) . He taught that God’s people have been made by God into a kingdom and that in Him they are priests and they reign and shall reign on the earth (Exodus 19:6; Revelation 1:6; 20:4) . The mustard seed growing into the full tree that it becomes is more than a picture of the faith of each individual believer. It is a more glorious picture of the kingdom of God, and its expansion, that shall have no end (Isaiah 9:6-7) . It is the picture of the kingdom of God to whom all the nations will flow to eventually (Isaiah 49:6; 60:3, 5) . His kingdom shall have no end.
Jesus is the central figure in the kingdom of God. Jesus is the one to whom every knee in heaven and on earth will bow and every tongue confess as Lord (Isaiah 45:23; Philippians 2:10) . Jesus is whom the Old Testament scriptures spoke about in law and in prophet (John 5:39) . Jesus explains this to two disciples on the road to Emmaus in Luke 23:14-27, when Luke testifies that Jesus, “… beginning with Moses and all the Prophets, he interpreted to them in all the Scriptures the things concerning himself.”- Luke 24:27
To not see Jesus in the Old Testament can lead to misunderstanding the whole message of the Old and New Testament along with the uniting thread that runs throughout the Testaments.
Jesus is preparing His disciples for the next phase of the kingdom. This next phase and how it fits into the biblical prophetic landscape would become more clear on the day of Pentecost in Acts 2:1. By the time Peter stands up and preaches the first sermon after the resurrection and ascension of Jesus, the very nature of Peter’s sermon indicates that much of what Jesus spoke about to the disciples for these 40 days was an explanation. It is a more detailed explanation of how the Old Testament prophecies have found their fulfillment in Jesus and how they shall find even more fulfillment in the arrival of the Holy Spirit and the expansion of the Gospel. There will be much more to be said regarding this in Acts 2:16-41.