The zeal of the convert is a term describing the very fervent devotion to new beliefs, which are completely different from one's old beliefs.[1][2][3] For example, Paul the Apostle, formally known as Saul of Tarsus was a Jewish Pharisees who persecuted Christians until he had a life changing vision on the road to Damascus and became a Christian missionary who spent his life spreading Christianity throughout the Roman empire and was later executed in Rome for his devout Christian beliefs.