The phrase, “speaking of the things pertaining to the kingdom of God” is the basis for the entire Ministry of Jesus of Nazareth, the Messiah (Christ). The same phrase communicated the intention for which the Father sent the Son of the Living God to be born and to “make known” the things pertaining to the Kingdom of God. The message of the Kingdom was the only thing on the mind of Jesus throughout His earthly ministry. The Kingdom of God is the central theme throughout all the books of the Bible!
Acts 1:1-4 (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:
Jesus of Nazareth was born in Bethlehem, raised in Egypt and Nazareth, and then ministered in the vicinity of the Sea of Galilee. He preached the Gospel (Good News) that the Kingdom of God is at hand to the House of Israel. He published His dynamic message in all the villages and small towns surrounding the sea of Galilee.
During the final weeks of His life, He ministered in Jerusalem and was totally rejected by the Religious Leaders and Ruling Elders of Israel, who finally had Him put Him to death by crucifixion. Three days later, He rose from the dead and then continued forty days to teach His disciples the things pertaining to the Kingdom of God (Acts 1:1-3).
Looking ahead to the final verses of the book of Acts (28:31) we discover Paul preached the Kingdom of God, and was teaching those things concerning Jesus Christ. This phrase is used at various times in the book of Acts and in the Church Epistles, indicating the importance placed upon the knowledge of the Kingdom of God as a present day reality to the followers of Christ.