Paul surely takes a low place. He realizes that it is only because of the Lord’s grace that he was given power to go into this service. Three things that he was, before he was saved. He did what he did through ignorance and unbelief.
V.14-15 In verse 13 he had received “mercy” — this was when he was not yet saved — but here we read of “grace,” “faith” and “love” when he has been saved. “Mercy” is for us when we were dead, “grace” is for us when we are alive in Christ. He was the chief sinner. Paul, before his conversion, had been a very moral man (Phil. 3:66Concerning zeal, persecuting the church; touching the righteousness which is in the law, blameless. (Philippians 3:6)), but he had hated Christ so that had made him the worst of sinners.
V.16 Paul, an example to all others of the grace of God.
V.18-20 “This charge” refers back to verse 3. And Timothy is encouraged to keep faith and a good conscience which we all need.