Summary: Paul had a personal encounter with the resurrected Lord, and was chosen, called, commissioned and sent by Jesus in the power of the Holy Spirit.
The Apostleship of Paul
Paul's testimony is that he is “the least of the apostles,” but he still saw the risen Lord and is a witness to the resurrection “as one born out of due time” (1 Corinthians 15:8-9). Paul asserted his apostleship by saying, “Am I not an apostle? Have I not seen Jesus Christ our Lord?” (1 Corinthians 9:1). Although Saul's companions on the Damascus road also witnessed the bright light and heard the sound of the voice, it was Saul alone who beheld Jesus (Acts 9:1-9).
The Damascus road experience was not just Paul's conversion, but also his commissioning to be the Apostle to the Gentiles. Ananias was told that Paul was a chosen vessel to bear the Lord's name before the Gentiles (Acts 9:15). Paul himself recalls Jesus saying, “I will deliver you from the people, and from the Gentiles, to whom I now send you” (Acts 26:17). The word “apostle” is literally “sent one.”
Paul's defence of the his apostleship is that he received it “not from men nor through man, but through Jesus Christ and God the Father who raised Him from the dead” (Galatians 1:1). Paul received the gospel, he says, by direct revelation from Jesus. Also, his commission as Apostle to the Gentiles came directly from Jesus (Galatians 1:11-12; Galatians 1:15-16).
It was three years before Paul went up to Jerusalem to meet Peter (Galatians 1:18). After the brethren in Damascus let him down in a basket over the wall of their city (Acts 9:25), Paul seems to have spent three years in Arabia (Galatians 1:17). Perhaps there he communed with his new-found Lord, and in meditation upon God's word embraced those teachings of which he was able to say later, “I received from the Lord,” and “this I say, and testify in the Lord,” and “I command, yet not I but the Lord” (1 Corinthians 11:23; 1 Corinthians 15:3; Ephesians 4:17; 1 Corinthians 7:10).
It was another fourteen years before Paul returned to Jerusalem with Barnabas and Titus, and there received the right hand of fellowship from Peter, James the Lord's brother, and John (Galatians 2:1; Galatians 2:9). This was the time of the famous Council of Jerusalem recorded in Acts 15.
From time to time Paul felt the need to reassert his apostleship, because it was so unique.
We see Peter's esteem of the Apostle Paul in his own later epistle to the churches of the dispersion: for Peter, the epistles of Paul are equal with “the other scriptures” (2 Peter 3:15-16).