While some sources say the Feast of the Conversion of Saint Paul is a relatively new development on the liturgical calendar, I have not found further detail of the feast's history.
The conversion story of Saint Paul is mentioned in a number of places in the New Testament, but the conversion story is told three times in the Acts of the Apostles. First, it is told as a third person narrative:
Now Saul, still breathing murderous threats against the disciples of the Lord, went to the high priest and asked him for letters to the synagogues in Damascus, that, if he should find any men or women who belonged to the Way, he might bring them back to Jerusalem in chains. On his journey, as he was nearing Damascus, a light from the sky suddenly flashed around him. He fell to the ground and heard a voice saying to him, "Saul, Saul, why are you persecuting me?" He said, "Who are you, sir?" The reply came, "I am Jesus, whom you are persecuting. Now get up and go into the city and you will be told what you must do." The men who were traveling with him stood speechless, for they heard the voice but could see no one. Saul got up from the ground, but when he opened his eyes he could see nothing; so they led him by the hand and brought him to Damascus. For three days he was unable to see, and he neither ate nor drank.(Acts 9, 1-19 NAB).
There was a disciple in Damascus named Ananias, and the Lord said to him in a vision, "Ananias." He answered, "Here I am, Lord." The Lord said to him, "Get up and go to the street called Straight and ask at the house of Judas for a man from Tarsus named Saul. He is there praying, and (in a vision) he has seen a man named Ananias come in and lay [his] hands on him, that he may regain his sight." But Ananias replied, "Lord, I have heard from many sources about this man, what evil things he has done to your holy ones in Jerusalem. And here he has authority from the chief priests to imprison all who call upon your name." But the Lord said to him, "Go, for this man is a chosen instrument of mine to carry my name before Gentiles, kings, and Israelites, and I will show him what he will have to suffer for my name." So Ananias went and entered the house; laying his hands on him, he said, "Saul, my brother, the Lord has sent me, Jesus who appeared to you on the way by which you came, that you may regain your sight and be filled with the holy Spirit." Immediately things like scales fell from his eyes and he regained his sight. He got up and was baptized, and when he had eaten, he recovered his strength.
Second, Saint Paul himself tells the story of his conversion when he is arrested in Jerusalem:
"My brothers and fathers, listen to what I am about to say to you in my defense." When they heard him addressing them in Hebrew they became all the more quiet. And he continued, "I am a Jew, born in Tarsus in Cilicia, but brought up in this city. At the feet of Gamaliel I was educated strictly in our ancestral law and was zealous for God, just as all of you are today. I persecuted this Way to death, binding both men and women and delivering them to prison. Even the high priest and the whole council of elders can testify on my behalf. For from them I even received letters to the brothers and set out for Damascus to bring back to Jerusalem in chains for punishment those there as well.(Acts 22, 1-21)
"On that journey as I drew near to Damascus, about noon a great light from the sky suddenly shone around me. I fell to the ground and heard a voice saying to me, 'Saul, Saul, why are you persecuting me?' I replied, 'Who are you, sir?' And he said to me, 'I am Jesus the Nazorean whom you are persecuting.' My companions saw the light but did not hear the voice of the one who spoke to me. I asked, 'What shall I do, sir?' The Lord answered me, 'Get up and go into Damascus, and there you will be told about everything appointed for you to do.' Since I could see nothing because of the brightness of that light, I was led by hand by my companions and entered Damascus.
"A certain Ananias, a devout observer of the law, and highly spoken of by all the Jews who lived there, came to me and stood there and said, 'Saul, my brother, regain your sight.' And at that very moment I regained my sight and saw him. Then he said, 'The God of our ancestors designated you to know his will, to see the Righteous One, and to hear the sound of his voice; for you will be his witness before all to what you have seen and heard. Now, why delay? Get up and have yourself baptized and your sins washed away, calling upon his name.'
"After I had returned to Jerusalem and while I was praying in the temple, I fell into a trance and saw the Lord saying to me, 'Hurry, leave Jerusalem at once, because they will not accept your testimony about me.' But I replied, 'Lord, they themselves know that from synagogue to synagogue I used to imprison and beat those who believed in you. And when the blood of your witness Stephen was being shed, I myself stood by giving my approval and keeping guard over the cloaks of his murderers.' Then he said to me, 'Go, I shall send you far away to the Gentiles.'"
Finally, Saint Paul describes his conversion for King Agrippa in his own defense:
I myself once thought that I had to do many things against the name of Jesus the Nazorean, and I did so in Jerusalem. I imprisoned many of the holy ones with the authorization I received from the chief priests, and when they were to be put to death I cast my vote against them. Many times, in synagogue after synagogue, I punished them in an attempt to force them to blaspheme; I was so enraged against them that I pursued them even to foreign cities.(Acts 16, 9-18)
"On one such occasion I was traveling to Damascus with the authorization and commission of the chief priests.At midday, along the way, O king, I saw a light from the sky, brighter than the sun, shining around me and my traveling companions.We all fell to the ground and I heard a voice saying to me in Hebrew, 'Saul, Saul, why are you persecuting me? It is hard for you to kick against the goad.'And I said, 'Who are you, sir?' And the Lord replied, 'I am Jesus whom you are persecuting.Get up now, and stand on your feet. I have appeared to you for this purpose, to appoint you as a servant and witness of what you have seen (of me) and what you will be shown. I shall deliver you from this people and from the Gentiles to whom I send you, to open their eyes that they may turn from darkness to light and from the power of Satan to God, so that they may obtain forgiveness of sins and an inheritance among those who have been consecrated by faith in me.'
As it is by now apparent, the recounting of Saint Paul's conversion thrice is an indication of the great importance it held for the Scripture writers. And its holds great importance for us too.
Each of us, no matter our circumstance or background, can be an instrument of the Lord on the earth. Even those, like Saint Paul, that have persecuted the Church can experience a conversion and go on to serve Christ. It is never too late and nothing any of us has ever done or failed to do can be too big for God. Have faith, that you too can be an apostle of Christ like Saint Paul.
IMAGE: The Conversion of St. Paul, Peter Paul Rubens (1577-1640).