John Piper, in a sermon “Overflowing Grace for All Who Believe”comments on the conversion of Saul in Acts 9
This is the kind of person that no one expects to be converted. His opposition is too deep and too articulate. So much of his life would be threatened if Christianity were true! And he has taken such a public stand that it would be utterly humiliating to change his mind and support what he had fought. It would be like Molly Yard becoming pro-life and doing rescues. Or Madalyn Murray O’hair believing in Jesus and pushing public prayer. Or Saddam Hussein getting converted and becoming a Christian missionary to Muslims in Saudi Arabia.
So what God wants us to see in this conversion is that the most unlikely people can be converted and are converted. God’s mercy and power are not limited to people who have been set up for Christianity by a good family or a church association or a clean moral track record. The chief of sinners was converted. And that means hope in evangelism and in your own faltering walk with the Lord.