His only gospel was the Gospel of the Kingdom according to Him. What He commanded was to reject the ways of man, repenting/changing our ways to the ways of the Kingdom which were His commandments.. to put the will of God before our own thus loving all as self. A counter-culture to the world man has made in our own self serving image. All else is later doctrine or religion. He told His apostles to spread the Gospel of the Kingdom. His Kingdom come, His will be done in earth as it is in Heaven.
Luke 16: 15 And he said unto them, Ye are they which justify yourselves before men; but God knoweth your hearts: for that which is highly esteemed among men is abomination in the sight of God. 16 The law and the prophets were until John: since that time the kingdom of God is preached, and every man presseth into it.
Luke 24: 47 And that repentance and remission of sins should be preached in his name among all nations, beginning at Jerusalem.
Luke 4: 43 And he said unto them, I must preach the kingdom of God to other cities also: for therefore am I sent.
Mark 1: 14 Now after that John was put in prison, Jesus came into Galilee, preaching the gospel of the kingdom of God, 15 And saying, The time is fulfilled, and the kingdom of God is at hand: repent ye, and believe the gospel.
Matthew 4: 23 And Jesus went about all Galilee, teaching in their synagogues, and preaching the gospel of the kingdom...
Luke 8: 1 And it came to pass afterward, that he went throughout every city and village, preaching and shewing the glad tidings of the kingdom of God: and the twelve were with him,
Matthew 7:21 Not every one that saith unto me, Lord, Lord, shall enter into the kingdom of heaven; but he that doeth the will of my Father which is in heaven.
Matthew 10: 7 And as ye go, preach, saying, The kingdom of heaven is at hand.
Mark 13:10 And the gospel must first be published among all nations.
Mark 16: 15 And he said unto them, Go ye into all the world, and preach the gospel to every creature. 16 He that believeth and is baptized [in the Holy spirit] shall be saved; but he that believeth not shall be damned.
Matthew 24: 14 And this gospel of the kingdom shall be preached in all the world for a witness unto all nations; and then shall the end come.
Matthew 23:13 But woe unto you, scribes and Pharisees, hypocrites! for ye shut up the kingdom of heaven against men: for ye neither go in yourselves, neither suffer ye them that are entering to go in.
Perhaps the end would come if they taught the right Gospel.
(Paul)
Acts 19:8 He (Paul) went into the synagogue, and spake boldly for the space of three months, disputing and persuading the things concerning the Kingdom of God
Acts 28: 23 And when they had appointed him a day, there came many to him into his lodging; to whom he expounded and testified the kingdom of God, persuading them concerning Jesus, both out of the law of Moses, and out of the prophets, from morning till evening. 24 And some believed the things which were spoken, and some believed not.
Acts 28: 30 And Paul dwelt two whole years in his own hired house, and received all that came in unto him, 31 Preaching the kingdom of God, and teaching those things which concern the Lord Jesus Christ, with all confidence, no man forbidding him.