THE KINGDOM AND ISRAEL
The kingdom was first formed among the children of Israel. In Exodus 19:6 the Lord told the children of Israel that they would be unto Him a kingdom of priests. Israel was the kingdom of God in the Old Testament.
THE FIRST THING PREACHED
IN THE NEW TESTAMENT
The kingdom was the first thing preached in the New Testament (Matt. 3:1-2; 4:17; Luke 9:1-2; 10:1, 9, 11; 9:60). John the Baptist, the first preacher of the New Testament age, told people, "Repent, for the kingdom of the heavens has drawn near." The first item preached in the New Testament is the kingdom, not heaven.
Many Christians think heaven and the kingdom are synonyms. They believe that to be in the kingdom is to be in heaven. Many think that when a Christian dies, his soul goes to the kingdom of the heavens. To them this means that it goes to heaven. This thought is not according to the divine revelation. Heaven is not the kingdom; neither is the kingdom of the heavens heaven.
PREACHED AS THE GOSPEL
In the New Testament the kingdom is preached as the gospel (Luke 4:43; Acts 8:12; Matt. 24:14; cf. Luke 18:29 and Mark 10:29). The kingdom is the gospel. In Luke 4:43 and Acts 8:12 the Greek word for preach is the verb form of gospel. The word used in these two verses means to preach something as the gospel. The Lord Jesus in Luke 4 and Philip in Acts 8 preached the kingdom as the gospel.
In Mark 10:29 the Lord refers to leaving all and following Him for the sake of the gospel. In Luke 18:29, however, the Lord speaks of leaving all and following Him for the sake of the kingdom of God. To leave all for the gospel means to leave all for the kingdom of God. Whatever we do for the kingdom of God is what we do for the gospel because in God’s eyes the kingdom and the gospel are synonymous.
INHERITING ETERNAL LIFE
From Mark 10:17, 23 we can see that to inherit eternal life is to enter into the kingdom. To receive eternal life is one thing; to inherit it is another. The New Testament makes the difference quite distinct, but many Christians do not notice this difference. When we believed in the Lord Jesus, we were regenerated and received eternal life. When we live by this life we have received, this life becomes our inheritance for our enjoyment. We receive eternal life today, but to inherit, to enter into, eternal life is a matter of the coming age. Whether or not you inherit eternal life as your blessing depends upon whether you are an overcomer or a defeated one. To enter into eternal life, to inherit eternal life, means to enter into the kingdom, to inherit the kingdom.
(The Basic Revelation in the Holy Scriptures, Chapter 6, by Witness Lee)