The only Google result for that is some RTF of a sermon or something. Can you provide a chapter and verse?
The first half of what you quote ("why persecutest thou Me") occurs twice, once in Acts 9:4 and once in Acts 22:7, but neither time is it followed by "And from that time, Saul was changed to Paul".
> But Saul, who was also known as Paul, filled with the Holy Spirit, fixed his gaze on him
"Many mistakenly assume the Lord changed Saul's name to Paul sometime after Saul converted from Judaism to Christianity, which happened during his encounter with Christ on the Road to Damascus (Acts 9:1-19). Unlike the instance of Jesus changing Simon's name to Kepha (Gk. Petros) as a way of signifying the special role he would play in the Church (Mt 16:18, Jn 1:41-42), in Paul's case there was no name change.
Saul of Tarsus was born a Jew, "circumcised on the eight day, of the race of Israel, or the tribe of Benjamin, a Hebrew of Hebrew parentage, in observance of the law a Pharisee" (Phil 3:5). The Hebrew name given him by his parents was Saul, but, because his father was a Roman citizen (and therefore Saul inherited Roman citizenship), Saul also had the Latin name Paul (Acts 16:37, 22:25-28), the custom of dual names being common in those days. Since he grew up in a strict Pharisee environment, the name Saul was by far the more appropriate name to go by. But after his conversion Saul determined to bring the gospel to the Gentiles, so he dusted off his Roman name and became known as Paul, a name Gentiles were accustomed to."
https://www.catholic.com/qa/why-did-god-change-sauls-name-to...