Acts 1:1-3 (KJV)
1 The former treatise have I made, O Theophilus, of all that Jesus began both to do and teach,
2 Until the day in which he was taken up, after that he through the Holy Ghost had given commandments unto the apostles whom he had chosen:
3 To whom also he shewed himself alive after his passion by many infallible proofs, being seen of them forty days, and speaking of the things pertaining to the kingdom of God:
Some have asked what are the things pertaining to the kingdom of God Jesus spoke of for forty days to His followers?
Briefly off the top of my head here is a short list of what the scriptures teach are the things concerning the kingdom of God:
1. In order to see the kingdom of God a man must be born again from above.
2. In order to enter into the kingdom of God a man must be born of the spirit.
3. Acknowledge the Creator as our Father in heaven.
4. Love God with all of our hearts, soul, mind and strength and love our neighbor as we love ourselves
5. Learn from the various accounts in the Gospels where Christ demonstrated how to live in this world as a kingdom citizen
4. Learn from The Sermon on the Mount from His Manifesto as King what the attitudes of a kingdom citizen are
5. Learn from the Book of Acts how ordinary people you and I became witnesses of the risen glorified king of the Universe. By speaking the Good News they proved by many infallible signs, miracles, and wonders the power of the spoken words of the good news about the kingdom of God
6. Learn from the church epistles how to walk in the spirit via the New Man that was created in you by God in righteousness and true holiness.
7. Learn from the Book of Hebrews how different Jesus The Messiah is from every other creature and what His role is Today in the lives of all who accept Him as Lord.
Then Philip went down to the city of Samaria, and preached Christ unto them. And the people with one accord gave heed unto those things which Philip spake, hearing and seeing the miracles which he did. For unclean spirits, crying with loud voice, came out of many that were possessed with them: and many taken with palsies, and that were lame, were healed. And there was great joy in that city.