Matthew 3:2

Repent; repentance is a change of mind with regard to sin, especially as committed against God, which leads a person to hate, confess, and forsake it.

Kingdom of heaven; the Messiah's reign as predicted by the prophets, or the sway of Christ's gospel and dispensation over the hearts, lives, and destinies of men, both in this world and in the next. This kingdom is spoken of in the Scriptures variously, in reference to its several aspects: first, in this world, as affecting the individual disciple in whose heart it is set up, as affecting the churches whom it gathers, and as influencing human society generally, even when not brought into the Christian church; and next, as extending from this world, through the judgment day, when it will be universally acknowledged, into the heavenly world, where it will reach its crowning glory. John the Baptist was its herald. Christ, after his resurrection and just before his ascension, declared his induction into it. Matthew 28:18. The millennium and the judgment are stages in its continuous progress; and the consummation of the mediatorial kingdom is described. 1 Corinthians 15:24; 1 Corinthians 15:28. Some texts in which the phrase is used refer mainly to one stage, and others to another, of its onward course. Men must hate and forsake their sins in order to be prepared for the kingdom of God. Proverbs 28:13.