Paul. Greatest sinner became God's Messenger

 God used the shameful past of Rahab and other prostitutes as a testimony to help other sinful people believe and be forgiven.

Paul's sinful past was not adultery or witchcraft, but self-righteous religious pride.

Paul's religious ambition drove him to be an outstanding biblical scholar, but there was no humility of love in his heart. His religion led him to persecute and murder followers of Jesus.

Paul became an enemy of Jesus and an enemy of the God he thought he served. Then came the day when everything changed.

As he neared Damascus on his journey, suddenly a light from heaven flashed around him.
He fell to the ground and heard a voice say to him, “Saul, Saul, why do you persecute me?”

“Who are you, Lord?” Saul asked. “I am Jesus, whom you are persecuting,” he replied.
“Now get up and go into the city, and you will be told what you must do.” Acts 9:3–6 NIV

God never forgot Paul's sin. It is recorded in the Bible, in the Word of God.

Paul also remembered his sin.

Here is a trustworthy saying that deserves full acceptance: Christ Jesus came into the world to save sinners—of whom I am the worst.

But for that very reason I was shown mercy so that in me, the worst of sinners, Christ Jesus might display his immense patience as an example for those who would believe in him and receive eternal life. 1 Tim 1:15–16 NIV

Paul was a living example of the mercy and grace that were at the centre of his message and ministry.
If there is extreme shame in your life, be encouraged.

“Do not be afraid; you will not be put to shame. Do not fear disgrace; you will not be humiliated. You will forget the shame of your youth and remember no more the reproach of your widowhood. Is 54:4 NIV

How can the deepest shame lead to eternal blessing in God's hands? Jesus hung stark naked on the cross to open the door to eternal glory for you and me.

Jesus forgave prostitutes and brutal religious leaders when they believed and repented. What can we learn from this. Pray for pimps, drug dealers and hypocritical preachers. No one is too bad to be forgiven.