Actually tuppence the Gospel that Jesus preached was the Gospel of the Kingdom of God/Heaven.
Matthew 4:23
23 And Jesus was going about in all Galilee, teaching in their synagogues, and proclaiming the gospel of the kingdom, and healing every kind of disease and every kind of sickness among the people.
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Paul refers to it as the Gospel of God:
Romans 1:1-7
1:1 Paul, a bond-servant of Christ Jesus, called as an apostle, set apart for the gospel of God, 2 which He promised beforehand through His prophets in the holy Scriptures, 3 concerning His Son, who was born of a descendant of David according to the flesh, 4 who was declared the Son of God with power by the resurrection from the dead, according to the Spirit of holiness, Jesus Christ our Lord, 5 through whom we have received grace and apostleship to bring about the obedience of faith among all the Gentiles, for His name's sake, 6 among whom you also are the called of Jesus Christ; 7 to all who are beloved of God in Rome, called as saints: Grace to you and peace from God our Father and the Lord Jesus Christ.
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But tell me tuppence why you have to infer Jesus is God when Paul never refers to Jesus as God; Paul always refers to Jesus as Lord?