Matthew Henry Commentary Galatians 2:15-19

"We being Jews by nature, and not sinners of the Gentiles, yet knowing that a man is not justified by the works of the law but through faith in Jesus Christ, even we believed on Christ Jesus, that we might be justified by faith in Christ, and not by the works of the law: because by the works of the law shall no flesh be justified. But if, while we sought to be justified in Christ, we ourselves also were found sinners, is Christ a minister of sin? God forbid. For if I build up again those things which I destroyed, I prove myself a transgressor. For I through the law died unto the law, that I might live unto God." — Galatians 2:15-19 (ASV)

Paul, having thus shown he was not inferior to any apostle, not even to Peter himself, speaks of the great foundational doctrine of the gospel. Why did we believe in Christ? Was it not so that we might be justified by the faith of Christ? If so, is it not foolish to go back to the law, and to expect to be justified by the merit of moral works, or sacrifices, or ceremonies? The occasion for this declaration undoubtedly arose from the ceremonial law, but the argument is just as strong against all dependence upon the works of the moral law regarding justification.

To give greater weight to this, it is added, But if, while we seek to be justified by Christ, we ourselves also are found sinners, is Christ the minister of sin? This would be very dishonorable to Christ and also very hurtful to them. By considering the law itself, Paul saw that justification was not to be expected by its works, and that there was now no further need for its sacrifices and cleansings, since they were done away in Christ, by His offering Himself up as a sacrifice for us.

Paul did not hope or fear anything from the law, any more than a dead man does from enemies. But the effect was not a careless, lawless life. This was necessary so that he might live to God and be devoted to Him through the motives and grace of the gospel. It is not a new prejudice, though a most unjust one, that the doctrine of justification by faith alone tends to encourage people in sin.

This is not so; for to use free grace, or its doctrine, as an occasion to live in sin is to try to make Christ the minister of sin, a thought at which all Christian hearts would shudder.