Matthew Bellisario: In fact, all St. Paul had was the Old Testament which was written in Greek, known as the Septuagint, and his interpretations were accepted by the illumination of the Holy Spirit, given to him by the authority passed down to him through the apostles. If you recall, even after Our Lord called him, he still went to have hands laid upon him to receive the apostolic authority and gifts of the Holy Spirit. (Acts 9:17-19) Only then was he “sent.” How was Saint Paul able to convert people without a Bible? The answer is simple, he did so by the authority of the apostles which were given authority to preach the Gospel from Christ Himself.
God calling and sending Paul prior to any laying on of hands, Acts 9:13-19: But Ananias answered, "Lord, I have heard from many about this man, how much evil he has done to your saints at Jerusalem. And here he has authority from the chief priests to bind all who call on your name." But the Lord said to him, "Go, for he is a chosen instrument of mine to carry my name before the Gentiles and kings and the children of Israel. For I will show him how much he must suffer for the sake of my name." So Ananias departed and entered the house. And laying his hands on him he said, "Brother Saul, the Lord Jesus who appeared to you on the road by which you came has sent me so that you may regain your sight and be filled with the Holy Spirit." And immediately something like scales fell from his eyes, and he regained his sight. Then he rose and was baptized; and taking food, he was strengthened.
Paul on his own calling: But when he who had set me apart before I was born, and who called me by his grace, was pleased to reveal his Son to me, in order that I might preach him among the Gentiles, I did not immediately consult with anyone; nor did I go up to Jerusalem to those who were apostles before me, but I went away into Arabia, and returned again to Damascus. … And from those who seemed to be influential (what they were makes no difference to me; God shows no partiality)—those, I say, who seemed influential added nothing to me.
Darrel Bock, Commentary on Act 9:17-19: It is significant that here a non-apostle is the mediator of the Spirit. The church's ministry is expanding in ways that mean that non-apostles will do important work.
(In Acts 9, Ananias is "a certain disciple." In Acts 22, he is described as "a devout man, according to the law, well spoken of by all the Jews who lived there." In neither case does he have any authority at all.)