Answer: It is true that Paul spread the gospel for many years and wrote many letters after being shone by the great light, but that doesn’t mean he really repented. Nowhere in his letters does it ever indicate that he really reflected on and knew his own evil behavior: his fanatical resistance of the Lord Jesus and persecution of His disciples. He just merely acknowledged that he was the foremost of all sinners. He never described his own nature and substance, nor did he say why he resisted the Lord Jesus, what his motive was.
Relevant Words of God:
In every age in which God personally does His own work, He uses a name that befits the age in order to encapsulate the work that He intends to do. He uses this particular name, one that possesses temporal significance, to represent His disposition in that age. This is God using the language of mankind to express His own disposition.
from “The Vision of God’s Work (3)” in The Word Appears in the Flesh