The man known as the apostle Paul began life as Saul of Tarsus (Acts 9:11). The account of his conversion to Christ is found in several places in the New Testament: Acts 9:1–19; 22:3–13; 26:12–18; and 1 Corinthians 15:9. From the moment he was saved, he began preaching about Jesus (Acts 9:20–21). Over the next several years, Paul traveled extensively, planting churches wherever he went. When not with those churches, he still carried the responsibility for them in his heart, like a father for his children (1 Corinthians 4:14; 1 Thessalonians 2:11). Much of the New Testament is made up of his letters to some of those churches. We know for certain that Paul wrote at least thirteen letters that are included in the New Testament. Scholars have debated whether or not Hebrews was written by Paul; if Paul wrote Hebrews, that would make his total contribution to the Bible fourteen books.
The following is a breakdown of the letters Paul wrote and the timeframes in which he wrote them: Galatians (AD 47) 1 and 2 Thessalonians (AD 49—51) 1 and 2 Corinthians and Romans (AD 52—56) Ephesians, Philemon, Colossians, and Philippians (AD 60—62, during Paul’s first Roman imprisonment) 1 Timothy and Titus (AD 62) 2 Timothy (AD 63—64, during Paul’s second Roman imprisonment)
Although Paul penned or dictated these letters, he makes it clear that he is speaking under the inspiration of the Holy Spirit. The other apostles, as well as the early church, accepted these letters as words from God (2 Peter 1:20–21; 3:15–16). Jesus Himself told Paul that he was sending him as a witness of all God would teach him.
“But rise, and stand upon thy feet: for I have appeared unto thee for this purpose, to make thee a minister and a witness both of these things which thou hast seen, and of those things in the which I will appear unto thee; Delivering thee from the people, and from the Gentiles, unto whom now I send thee, To open their eyes, and to turn them from darkness to light, and from the power of Satan unto God, that they may receive forgiveness of sins, and inheritance among them which are sanctified by faith that is in me.” Acts 26:16–18