The Apostle Paul wasn’t always an apostle.
His reputation was quite different before his apostolic calling.
Paul hated Christians, he persecuted Christians, he even killed Christians.
That is, until one day he became one.
Paul’s transformation was so powerful and miraculous that he became a missionary. Paul began planting churches all over Eastern Europe and Asia Minor. He later ended up writing letters to these churches encouraging them to stay on the right path. These letters became scripture making up 13 of the 27 books of the New Testament.
He had two names: Saul and Paul.
It is a common misconception that after his conversion God had changed Saul’s name to Paul. That’s actually not true. There is no biblical basis for this whatsoever. In the Old Testament it wasn’t uncommon for God to give people new names when they had been called by him. But this is not one of those cases.
He had two names the whole time. His Hebrew given name was Saul and his Greek given name was Paul. God doesn’t change Saul’s name. Luke does. Luke was a doctor that wrote the book of Acts. In this book he records Paul’s conversion experience and his missionary journeys. Luke refers to him as Saul up until he begins his missionary journey, then he starts calling him Paul. Most likely because that’s what he went by when he started reaching Gentiles and Greeks, he went by his Greek name.
Not everything you hear is true. Even if it’s been said for a really long time.
Study for yourself.
You might even find some treasure.