Its first to the Jew and then to the Greeks. There is only one Gospel.
Romans 1:16
For I am not ashamed of the Gospel of Christ, for it is the power of God unto salvation to every one who believeth, to the Jew first and also to the Greek.
What Gospel was Jesus teaching?
Matthew 4:12 Now when Jesus had heard that John was cast into prison, He departed into Galilee; 4:13 And leaving Nazareth, He came and dwelt in Capernaum, which is upon the sea coast, in the borders of Zabulon and Nephthalim: 4:14 That it might be fulfilled which was spoken by Esaias the prophet, saying, 4:15 The land of Zabulon, and the land of Nephthalim, by the way of the sea, beyond Jordan, Galilee of the Gentiles; 4:16 The people which sat in darkness saw great light; and to them which sat in the region and shadow of death light is sprung up.
4:17 From that time Jesus began to preach, and to say, Repent: for the Kingdom of Heaven is at hand. 4:18 And Jesus, walking by the sea of Galilee, saw two brethren, Simon called Peter, and Andrew his brother, casting a net into the sea: for they were fishers. 4:19 And He saith unto them, Follow Me, and I will make you fishers of men. 4:20 And they straightway left their nets, and followed Him. 4:21 And going on from thence, He saw other two brethren, James the son of Zebedee, and John his brother, in a ship with Zebedee their father, mending their nets; and He called them. 4:22 And they immediately left the ship and their father, and followed Him. 4:23 And Jesus went about all Galilee, teaching in their synagogues, and preaching the Gospel of the Kingdom, and healing all manner of sickness and all manner of disease among the people.
What Gospel were the Twelve Apostles teaching?
Matthew 10:2 Now the names of the twelve apostles are these; The first, Simon, who is called Peter, and Andrew his brother; James the son of Zebedee, and John his brother; 10:3 Philip, and Bartholomew; Thomas, and Matthew the publican; James the son of Alphaeus, and Lebbaeus, whose surname was Thaddaeus; 10:4 Simon the Canaanite, and Judas Iscariot, who also betrayed Him. 10:5 These twelve Jesus sent forth, and commanded them, saying, Go not into the way of the Gentiles, and into any city of the Samaritans enter ye not: 10:6 But go rather to the lost sheep of the house of Israel. 10:7 And as ye go, preach, saying, The Kingdom of Heaven is at hand.
What Gospel did they continue to teach?
Matthew 28:16 Then the eleven Disciples went away into Galilee, into a mountain where Jesus had appointed them. 28:17 And when they saw Him, they worshipped Him: but some doubted. 28:18 And Jesus came and spake unto them, saying, All power is given unto Me in heaven and in earth. 28:19 Go ye therefore, and teach all nations, baptizing them in the name of the Father, and of the Son, and of the Holy Ghost: 28:20 Teaching them to observe all things whatsoever I have commanded you: and, lo, I am with you alway, even unto the end of the world. Amen. (John 17:20)
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.
John 14:24 He that loveth Me not keepeth not My words: and the word which ye hear is not Mine, but the Father's which sent Me. (John 12:48-50)
Revelation 12:17 And the dragon was wroth with the woman, and went to make war with the remnant of her seed, which keep the Commandments of God, and have the Testimony of Jesus Christ.