Mr 1:15 And saying, The time is fulfilled, and the kingdom of God is at hand: repent ye, and believe the gospel. The "kingdom of God is at hand" refers to the PERSON of the King incarnated in Jesus Christ. John went before "Him" to prepare "His way" saying the kingdom of God is at hand - Mk. 1:1-3. The "gospel of the kingdom" is expounded in John 3:1-20 and John 3:36 showing in detail what the "good news" of the kingdom was or how to enter the kingdom (1) by new birth - Jn. 3:1-9 and faith in Christ - Jn. 3:15-16 that transforms your very nature - Jn. 3:18-20 removing you out from under the wrath of God - Jn. 3:36. The Great Commission to ALL NATIONS was to preach "repentance" in connection with the gospel and they went out preaching the gospel of the kingdom: TO THE SAMARITANS Ac 8:12 But when they believed Philip preaching the things concerning the kingdom of God, and the name of Jesus Christ, they were baptized, both men and women. TO THE JEWS Ac 19:8 And he went into the synagogue, and spake boldly for the space of three months, disputing and persuading the things concerning the kingdom of God. TO THE GENTILES Ac 20:25 And now, behold, I know that ye all, among whom I have gone preaching the kingdom of God, shall see my face no more. TO ANYONE WHO CAME TO SEE HIM Ac 28:31 Preaching the kingdom of God, and teaching those things which concern the Lord Jesus Christ, with all confidence, no man forbidding him. Repentance is toward God and is turning from EVERYTHING about self and what self can do to be saved but entirely dying to self and RESTING in the good news of Jesus Christ.