Pauline Christianity is a term applied by those who claim that Jesus taught one thing, and Paul taught something completely different. They believe that the Christianity of today has little to do with Jesus’ teachings; rather, it is the product of Paul’s corruption of those teachings.
In short, according to them, Paul was a charlatan, an evangelical huckster who succeeded in twisting Jesus’ message of love into something Jesus himself would never recognize. It was Paul, not Jesus, who originated the “Christianity” of today.
We on the other hand, believe that the New Testament is a unified whole: the Gospels present the life and work of Jesus the Messiah; the Epistles explain the meaning and scope of Jesus’ work and apply it to daily living. For example, Matthew 28 narrates the fact of Jesus’ resurrection, and 1 Corinthians 15 explains the significance of His resurrection. The same Holy Spirit who inspired the Gospels also inspired the Epistles to give us a fuller understanding of God’s plan of salvation.
Commonly, many of those who hold to the negative theory about Paul, also believe the following:
1) Jesus was not divine. He never claimed to be God, and he never intended to start a new religion.
2) The Bible is not an inspired book and is riddled with contradictions. None of the Bible, except possibly the book of James, was written by anyone who knew Jesus. There are fragments of Jesus’ teachings in the Gospels, but it is difficult to discern what he really said.
3) Paul was never a Pharisee and was not highly educated. His “conversion” was either a personal hallucinogenic experience or an outright fraud. His claims to be an apostle were attempts to further his own authority in the church.
4) Pauline theological “inventions” include a) the deity of Jesus; b) salvation by grace through faith; c) salvation through the blood of Jesus; d) the sinless nature of Jesus; e) the concept of original sin; and f) the Holy Spirit. None of these “new doctrines” were accepted by Jesus’ true followers.
5) The Gnostic Gospels are closer to the truth about Jesus than are the traditional four Gospels of the Bible.
The concept of “Pauline Christianity” represents an outright attack on the Bible as the Word of God. Adherents of the “Pauline Christianity” theory are truly misrepresenting Jesus’ teachings. They choose to believe His words on love but deny His teachings on judgment (such as Matthew 24). They insist on a human Jesus, denying His divinity, although Jesus plainly taught His equality with God in passages such as John 10:30. They want a “loving” Jesus without having to accept Him as Lord and Savior.
Interestingly, Paul’s credentials as an apostle were attacked, even in his own lifetime, by those who desired to lead the church into legalism and other errant ideologies. Paul defends himself from the spurious attacks of false teachers in 1 Corinthians 9; 2 Corinthians 12; and Galatians 1.
Paul’s apostleship is attested to by the miracles he performed (Romans 15:19), the training he received (Galatians 1:15-20), and the testimony of the other apostles. Peter, far from being Paul’s enemy, wrote this about him: “Our dear brother Paul also wrote you with the wisdom that God gave him. He writes the same way in all his letters, speaking in them of these matters. His letters contain some things that are hard to understand, which ignorant and unstable people distort, as they do the other Scriptures, to their own destruction” (2 Peter 3:15-16).
(The above are extracts from an article by GotQuestions.Org – https://www.gotquestions.org/Pauline-Christianity.html )
Don Stewart, from The Blue Letter Bible gives us some clarity about Paul:
What evidence do we have to call Paul’s writings Scripture?
WHO WAS PAUL?
We have no physical description of Saul of Tarsus given to us in Scripture. Early tradition says that he was a small man with a bald head. No matter what he looked liked, his writings have become part of the Word of God as found in the New Testament.
He was born Saul of Tarsus – a city which is in modern-day Turkey. Tarsus had been part of the Greek world for some time. Although the family of Saul were Jews, Saul himself was a Roman citizen.
While still a young man Saul travelled to Jerusalem to train as a Rabbi. In Jerusalem, he became acquainted with a group of people who believed Jesus of Nazareth to be the Messiah. Saul relentlessly persecuted these people while all the time thinking that he was serving God.
THE CONVERSION OF SAUL OF TARSUS
While heading for Damascus to further jail believers in Jesus, Saul had a blinding vision that knocked him to the ground. The voice that spoke to Saul identified Himself as Jesus of Nazareth – the one whom he had been persecuting. Thus, began one of the great turnarounds in history. The greatest antagonist of the Christian faith – Saul of Tarsus – became its greatest missionary – the Apostle Paul. During his lifetime he penned thirteen different works that have become part of the New Testament. It is impossible to overestimate the influence that Paul played in the spread of the Christian faith.
HE BELIEVED HIS MESSAGE TO BE DIVINE
The first thing that must be noticed is that Paul believed his message to be divine. He wrote:
“If anyone thinks himself to be a prophet or spiritual, let him acknowledge that the things which I write to you are the commandments of the Lord” (1 Corinthians 14:37).
He wrote to the church at Thessalonica:
“And for this reason we also constantly thank God that when you received from us the word of God’s message, you accepted it not as the word of men, but for what it really is, the word of God, which also performs its work in you who believe” (1 Thessalonians 2:13).
PAUL SPOKE OF “MY GOSPEL”
Paul spoke of “my gospel.” He said the preaching of Jesus Christ had been kept secret but now had been revealed.
“Now to him who is able to establish you according to my gospel and the preaching of Jesus Christ, according to the revelation of the mystery which has been kept secret for long ages past, but now is manifested, and by the Scriptures of the prophets, according to the commandment of the eternal God, has been made known to all the nations, leading to obedience of faith” (Romans 16:25,26).
However, believing to have a divine message does not make it so. What evidence do we have of this message having been sent from God?
PAUL RECEIVED DIRECT REVELATION FROM THE LORD
The Bible teaches that Paul received direct revelation from God. Paul wrote:
“Have I not seen Jesus Christ our Lord?” (1 Corinthians 9:1).
After an encounter with the ascended Jesus on the Damascus road, Paul had it explained by Ananias:
“The God of our fathers has chosen you that you should know his will, and see the Just One, and hear the voice of his mouth. For you will be his witness to all men of what you have seen and heard “ (Acts 22:14,15).
DISOBEYING HIS WRITINGS BRINGS DISCIPLINE
Paul said that anyone who disobeyed his writings was to be disciplined by the local church. He wrote:
“If anyone does not obey our instruction in this letter, take special note of that person and do not associate with him, so that he will be put to shame” (2 Thessalonians 3:14).
To the Corinthians he wrote:
“I already gave you a warning when I was with you the second time. I now repeat it while absent: On my return I will not spare those who sinned earlier or any of the others, since you are demanding proof that Christ is speaking through me. He is not weak in dealing with you, but is powerful among you” (2 Corinthians 13:2-3).
Paul also wrote:
“If anybody thinks he is a prophet or spiritually gifted, let him acknowledge that what I am writing to you is the Lord’s command. If he ignores this, he himself will be ignored” (1 Corinthians 14:37,38).
HIS WRITINGS WERE CONSIDERED SCRIPTURE DURING HIS LIFETIME
The final point is that the New Testament recognized Paul’s writing as Scripture. Peter wrote:
“Our beloved brother Paul, according to the wisdom given to him, has written to you, as also in all his letters, speaking in them of these things, in which some things are hard to understand, which those who are untaught and unstable twist to their own destruction, as they do the rest of the Scriptures” (2 Peter 3:15,16).
The writings of Paul complete the New Testament. He was the chosen instrument to explain the meaning of the two comings of Jesus Christ.
Saul of Tarsus was a great enemy of the church. However, he was converted on the road to Damascus while in the midst of persecuting Christians. He became the Apostle Paul – the greatest missionary the church has ever seen.
Paul was given the task of explaining the ministry of Christ to the Gentile (non-Jewish) world.
We find that he received direct revelation from the Lord. Paul also believed his message to be divine. The Apostle Peter confirmed Paul’s words as Scripture. He was God’s chosen instrument to reveal much about the central truths of the Christian faith. Paul also explained the necessity of the two comings of Christ.
(Source: https://www.blueletterbible.org/faq/don_stewart/don_stewart_1242.cfm )