To understand why Paul is the apostle to the Gentiles, it will help to understand why Moses is the lawgiver, why the entire Law is summed up as the "Law of Moses", even though the Law was given by God.
Even Jesus himself referred to the Law as "The Law of Moses". As he is living under the law, he is also subjected to Moses. (John 5:46, Matthew 19:8, Matthew 23:1, 2, Mark 7:9, 10).
Moses authority has been challenged before by the Jews, who wanted to hear directly from God instead. In the famous story recounted in Numbers 12
And Miriam and Aaron spake against Moses because of the Ethiopian woman whom he had married: for he had married an Ethiopian woman.
2 And they said, Hath the Lord indeed spoken only by Moses? hath he not spoken also by us? And the Lord heard it.
3 (Now the man Moses was very meek, above all the men which were upon the face of the earth.)
8 With him will I speak mouth to mouth, even apparently, and not in dark speeches; and the similitude of the Lord shall he behold: wherefore then were ye not afraid to speak against my servant Moses?
9 And the anger of the Lord was kindled against them; and he departed.
Likewise, almost all of us are Gentiles here. We belong to the Church, and in this age of grace, Paul is our apostle, his importance is equivalent to Moses, as the lawgiver to the Jews.
Paul's words are the words of the ascended Lord Jesus to his Church, and we will do well to follow what Paul is saying, as instructed in 1 Corinthians 14:37
If any man think himself to be a prophet, or spiritual, let him acknowledge that the things that I write unto you are the commandments of the Lord.
The 12:
Acts 21:25, “But as for the Gentiles who have believed, we have sent a letter with our judgment that they should
abstain from what has been sacrificed to idols, and from blood, and from what has been strangled, and from sexual immorality.”
Paul:
1 Corinthians 10:25, “
Eat anything sold in the meat market without raising questions of conscience.”
Matthew 28:19-20, “Therefore, as you go,
disciple all the nations, baptizing them in the name of the Father, and of the Son, and of the Holy Spirit, teaching them to obey all that I have commanded you. And remember, I am with you each and every day until the end of the age.”
Peter was martyred in Rome about 66-68 AD, during the persecution under Emperor Nero. Origen says Peter was crucified, upside down at his request, because he did not feel he was worthy to die in the same manner as the Messiah.
Andrew went to the "Land of the Man-Eaters," in what is in modern times Russia. Christians there he was the first to bring the gospel to their land. He also preached in Asia Minor, modern-day Turkey, and in Greece, Patrae in Achaia is where he is said to have been crucified on an x-shaped cross he called to the crowds and taught them about Jesus Christ and how they might be saved, thus he was sharing the gospel up until the very time of his death.
Thomas was probably most active in the area east of Syria. Tradition has him preaching as far east as Edessa and India, where the ancient Marthoma Christians revere him as their founder. They claim that he died there when pierced through with the spears of four soldiers.
Philip possibly had a powerful ministry in Carthage in North Africa and then in Asia Minor, in Phrygia and died at Hierapolis. The tomb of the Apostle Phillip is found in Hierapolis where he converted the wife of a Roman proconsul, the proconsul had Philip arrested and cruelly put to death. He was impaled by iron hooks in his ankles and hung upside down to die.
Matthew the tax collector and writer of a Gospel, ministered to the Persians, Parthians, Medes and Ethiopians, he was staked or impaled to the earth by spears and then beheaded.
Bartholomew/Nathaniel had widespread missionary travels attributed to him by tradition: to India with Thomas, back to Armenia, and also to Ethiopia and Southern Arabia. There are various accounts of how he met his death as a martyr for the gospel. Most agree that he was basically flayed to death by whip, where he was literally torn to shreds, martyred in Armenia, he too must have been involved in the Great Commission and taking the good news into that part of the world. Apparently, he became a missionary to Asia Minor.
James the son of Alpheus, is one of at least three James referred to in the New Testament. There is some confusion as to which is which, but this James is reckoned to have ministered in Syria. The Jewish historian Josephus reported the James was thrown down from the temple by the scribes and Pharisees; he was then stoned, and his brains dashed out with a club.
James the son of Zebedee: He was beheaded by Herod Agrippa the 1st shortly before the day of the Passover, in the year 44 or about 11 years after the death of Christ. (Acts 12: 1-2)
Simon the Zealot so the story goes, ministered in Persia and he was was crucified after refusing to sacrifice to the sun god.
Matthais was the apostle chosen to replace Judas in fulfillment of prophecy (Psalm 69:25, 109:8). sentenced to death by the Sanhedrin and stoned.
When Matthias was already dead, the Jews, to hide their malefaction, cut off his head as an enemy of Caesar. According to several historians, the Apostle Matthias was crucified, and indicate that he instead died at Colchis, some even say he was burned.
Jude (Thaddeus): according to tradition Jude taught in Armenia, Syria and Persia where he was martyred by crucifixion. Tradition tells us he was buried in Kara Kalisa in what is now Iran.
John was imprisoned during Domitian's persecution in the middle 90's, he was exiled to the island of Patmos, were he was given visions and wrote the Revelation of Jesus Christ. He was later freed and went to Turkey, perhaps on a mission to establish churches there. John is the only one of the company generally thought to have died a natural death from old age between 90 AD to 120 AD. He was the leader of the church in the Ephesus area and is said to have taken care of Mary the mother of Jesus in his home.