The Zondervan Pictorial Encyclopedia of the Bible says this about the Kingdom of God: "The word 'kingdom' is found fifty-five times in Matthew; twenty times in Mark, forty-six times in Luke and five times in John. When allowance is made for the use of the word to refer to secular kingdoms and for parallel verses of the same sayings of Jesus, the phrase 'the Kingdom of God' and equivalent expressions (e.g., 'Kingdom of heaven,' 'his kingdom') occur about eighty times . . . These statistics show the great importance of the concept in the teachings of Jesus . . . There can, therefore, be little doubt that the phrase 'the Kingdom of God' expresses the main theme of His teaching" (Vol. III, Zondervan, 1976, p. 804).
Jesus equated receiving salvation with entering the Kingdom (Matthew 19:16-24), and He explained the loss of salvation in terms of banishment from the Kingdom (Luke 13:28). The message of salvation is called "the word of the kingdom" (Matthew 13:19). The hope and comfort of a Christian are said to be in entering the Kingdom (Mark 10:15).
The goal of a Christian is to "seek first the kingdom of God" (Matthew 6:33). Righteous people are called "sons of the kingdom" (Matthew 13:38). The theme of many of Christ's parables is God's Kingdom (Matthew 13:44-47).
Some of the many biblical terms for and references to the Kingdom of God are explained in our free booklet The Gospel of the Kingdom.