Many verses in the New Testament show the need of exercise for the kingdom. Acts 14:22 says, “Establishing the souls of the disciples, exhorting them to continue in the faith and saying that through many tribulations we must enter into the kingdom of God.” By comparing this verse with John 3:5, we can see a great difference. John 3:5 simply says that by being born of water and the Spirit we can enter into the kingdom of God. According to John, entering the kingdom is a matter of another birth. But Acts 14 says that we must suffer much tribulation to enter into the kingdom of God. These two verses show two aspects. To enter into the kingdom of God is one thing, but to enter into it in the way of inheritance is another. If we would inherit the kingdom of God, we must suffer the tribulation. We must be tested and exercised.
We can see the same principle in 1 Corinthians 5 and 6. Chapter 5 indicates that a brother who is living in fornication will still be saved. Even such a sinful, defeated believer will still be saved. But in chapter 6 we are told that fornicators will not inherit the kingdom of God. This means that a fornicator cannot enjoy or inherit the kingdom of the heavens as a reward.
Now let us read Ephesians 5:3-5: “But fornication and all uncleanness or greediness, let it not even be named among you, as is fitting for saints, and obscenity and foolish talking or sly, filthy jesting, which are not becoming, but rather the giving of thanks. For this you realize, knowing that every fornicator or unclean person or greedy person (who is an idolater) has no inheritance in the kingdom of Christ and of God.” The kingdom of Christ and of God is the part of the kingdom of God which is the kingdom of the heavens. As a whole, it is the kingdom of God, but particularly, it is the kingdom of the heavens. In the kingdom of God and of Christ there is no inheritance for the sinful one. If you are still in filthiness and sinfulness, although you are a saint, a saved one, you will have no inheritance in the kingdom of God and of Christ.
Galatians 5:19-21 says, “And the works of the flesh are manifest, which are such things as fornication, uncleanness, lasciviousness, idolatry, sorcery, enmities, strife, jealousy, outbursts of anger, factions, divisions, sects, envyings, bouts of drunkenness, carousings, and things like these, of which I tell you beforehand, even as I have said before, that those who practice such things will not inherit the kingdom of God.” Thus, three portions of the Bible, 1 Corinthians 6, Ephesians 5, and Galatians 5 tell us basically the same thing: you may be a saved person, but if you are still living in sin and filthiness, you will not inherit the kingdom of God. You will have no share in the manifestation of the kingdom of the heavens, because you are not qualified.
Second Thessalonians 1:5 says, “A plain indication of the righteous judgment of God, that you may be accounted worthy of the kingdom of God, for which also you suffer.” This verse indicates that to suffer persecution causes one to be worthy of the kingdom of God. This can enable one to inherit the kingdom of God.
Let us also read 2 Timothy 4:18, 7-8, and 1: “The Lord will deliver me from every evil work and will save me into His heavenly kingdom, to whom be the glory forever and ever. Amen.” “I have fought the good fight; I have finished the course; I have kept the faith. Henceforth there is laid up for me the crown of righteousness, with which the Lord, the righteous Judge, will recompense me in that day, and not only me but also all those who have loved His appearing.” “I solemnly charge you before God and Christ Jesus, who is to judge the living and the dead, and by His appearing and His kingdom.” These verses, written near the end of Paul’s life, indicate that he was sure of being in the heavenly kingdom, because he had fought a good fight, he had run the course well, and he had kept the faith.