Galatians 1:23

But they only heard say, He that once persecuted us now preacheth the faith of which he once made havoc.

Nothing in the New Testament more emphatically nails down the fact that Paul did not "bring a brand-new way of salvation." The gospel he preached was exactly the truth he persecuted. The conflict which underlies Paul's extensive writings on faith vs. law is not a conflict between two ways of understanding the gospel; but it is a conflict between the one faith vs. the Law of Moses as interpreted by the Judaizers who made keeping it necessary and essential unto salvation (Acts 15:1).

If one might be permitted to speculate upon the reason why Almighty God moved to supplement the personnel of the original Twelve by the addition of Paul, the reason must be sought in the fact that in one essential particular the Twelve did not fully comprehend the absolute freedom (a term Paul himself used to describe the break in Romans 7:1ff) of Christianity from the totality of Judaism. That God Almighty could not allow, no matter what miracles were involved in order to prevent it. Paul was surely one of those miracles. Paul never went beyond Jesus' revelation to the Twelve, except in the application of the gospel to all people, and to Gentiles in particular, instead of merely to the Jews. The reason Paul was able to do that did not derive from any difference in Christ's revelation to himself and to the Twelve; for they had all received the same revelation Paul was given. Peter, for example, on Pentecost had plainly declared that the gospel was for "them that are afar off," obviously meaning Gentiles. The thing that enabled Paul more readily and effectively to apply this truth (although all of the apostles eventually succeeded in doing so) was his greater knowledge of the Old Testament, and in addition, many elements in the personality of the man himself.

Dummelow's comment on this verse is illustrative of the type of thinking that often clutters the minds of scholars on this question. He wrote: "Preacheth the faith proclaims the necessity of trust in Christ as the sole essential to salvation!"[51] Indeed, indeed! Paul was preaching the same gospel Peter preached, and Peter commanded believers to "repent and be baptized" in order to receive the remission of sins (Acts 2:38); and this verse is an affirmation that Paul preached exactly the same gospel.