He does so by briefly recounting his own experience of conversion in verses 12–14. He begins by thanking God for calling him into His service despite his past sins. He says in verse 12 that God “judged him faithful.” Since he’s talking here about his transition from unbeliever to believer, he can’t have in mind here any kind of ongoing faithfulness in his Christian life. Instead, he’s referring to the moment of his conversion.
At that moment, God “judged him faithful” in the sense of pronouncing judgment upon him. And that judgment was “faithful,” or “righteous.” Yet that judgment could not have been on the basis of his behavior at the time, for he says in verse 13 that he was “a blasphemer, persecutor, and insolent opponent.”
Some people have very dramatic conversion stories and others do not. Actually, however, the transition from unbeliever to believer is always dramatic, because it involves a complete remaking of the person and his direction in life. It is heart surgery—we are given a new heart, one that is soft and sensitive to the things of God, one that is able to respond to Him.
Paul exemplified this transition. His story is well known. Before his conversion, he was a fierce opponent of Christianity. He was there at the stoning of Stephen (Acts 7); he persecuted Christians; he sought them out and put them in prison. In fact, when he converted, he was on his way to Damascus to search for and imprison Christians (Acts 9).
Paul calls himself a blasphemer because he refused to recognize Christ as God. He was a persecutor because he opposed the church. And he was an “insolent opponent,” like a madman, someone wild and out of control.
But then something changed. In verse 13, Paul tells us: “But I received mercy because I had acted ignorantly in unbelief.” He highlights the mercy of God in saving him, but he does not excuse his sin. To do so would be to destroy his need for mercy. In saying he had acted ignorantly, Paul is applying a category from the Jewish law. He’s saying that he sinned without knowing it. The law made provisions for sins committed in ignorance. Nevertheless, some kind of sacrifice had to be made for such sins of ignorance, for they were still sins.
Before Paul was saved, he believed he was zealous for God. He opposed the church because he thought it was an abomination. He didn’t realize it, but he was opposing God. And he was trying to earn salvation through his good works, through his zeal in keeping the law and in opposing the church. Such an attitude attempts to force God to accept us, to bring something before Him that we can point to and say: “Here. Because of this, You must approve of me.”
There is no such thing that Paul could do to deserve the Lord’s acceptance of him. If Paul was to be saved, it would have to be a purely gracious act, an act of pure mercy. Sinners cannot earn their salvation through their works. Paul came to recognize this truth after his conversion, and he locates the transition from his former way of life here, in God’s receiving mercy.
At that point, Paul says in verse 14, “the grace of our Lord overflowed for me with the faith and love that are in Christ Jesus.” The grace and love of Christ overflowed into Paul’s life and poured into his life in such a way that afterward, Paul’s life was characterized by faith and love. He had faith in Christ, and he loved God, and that affected how he lived his life. His life was marked by service to God, as he says in verse 12.
This is the other side of the transition. Because of this new state, it would have been inconceivable for him to continue in his previous way of life.
Some people today say that because we are saved by grace, what we do doesn’t matter. But Paul would have none of this. In pointing to his experience, he is saying that a fundamental change in how we live our lives is central to conversion. Having been saved by the mercy of God and given new hearts, we simply cannot continue to live as we once did.
Of course, on this side of glory, sin remains. Paul himself recognized this and grieved about it (see especially Rom. 7). But the mercy of God’s acting in conversion calls us to strive for holiness. One of the marks of believers is a struggle with sin, by the power of the Holy Spirit.
Salvation, according to Paul’s pattern, is undeserved mercy. This undeserved mercy sparks a fundamental change in our lives. We receive, by God’s mercy, a new heart. We are pronounced righteous by virtue of our faith in Christ.
Afterward, by God’s grace, we strive, not always perfectly and not always consistently, but by the power of the Holy Spirit, to leave behind our former lives and to pursue holiness. This is part of what it means to be saved.