1 Timothy 1:13
Who was before a blasphemer, and a persecutor, and injurious: but I obtained mercy, because I did it ignorantly in unbelief. Who was before a blasphemer, and a persecutor, and injurious: but I obtained mercy, because I did it ignorantly in unbelief.
Paul's former life in the flesh was wholly and utterly against Christ as a blasphemer and persecutor and injurious person, a violent opponent of Christians who pursued God's people even to death. His blasphemy was not distant dislike but treating Christ's name with contempt and using every means in his power to make others blaspheme it. He did all those hateful things in ignorance and unbelief because he did not know Christ and misunderstood what constitutes true godliness and true religion.
When the commandment reached his conscience, sin was seen in its true character, and through Christ he saw himself as guilty and as so great a sinner. Despite that past he obtained mercy and forgiveness, with Christ accepting his repentance. The same forgiveness is held out to one who breaks away from sin, makes thorough work of repentance, and forever relies on His power and grace under the influence of the Holy Spirit.
The turning point came when Christ revealed Himself to Paul and arrested him on his route of persecuting followers, so that the whole man was converted and born again, and was later converted. Afterward his whole life and religious experience was changed to be wholly for Christ as a humble, happy, devoted and steadfast servant, devoting his life to serving and honoring the One he had treated with contempt and to winning souls to Him despite opposition and persecution. That faithfulness to Christ stayed steadfastly before him in all his varied work of laboring with his hands, traveling, establishing churches, and writing letters, with the one great purpose of serving and honoring Him.
His example shows that Christ's mercy and longsuffering can reach even one who has opposed Him, so those who oppose the truth ignorantly while following the light they have, without rejecting light and evidence or willfully resisting truth, may still be converted and won to Christ. Such people should therefore not be condemned as beyond hope, but treated as honest because their souls are precious to God, and not pushed further into unbelief by word or deed. Still, ignorance does not lessen the grave danger of refusing to seek the truth.