The following is an excerpt from The MacArthur New Testament Commentary on 1 Corinthians 9.

For though I am free from all men, I have made myself a slave to all, that I might win the more. And to the Jews I became as a Jew, that I might win Jews; to those who are under the Law, as under the Law, though not being myself under the Law, that I might win those who are under the Law; to those who are without law, as without law, though not being without the law of God but under the law of Christ, that I might win those who are without law. To the weak I became weak, that I might win the weak; I have become all things to all men, that I may by all means save some. And I do all things for the sake of the gospel, that I may become a fellow partaker of it. (9:19–23)

The primary purpose of Paul’s not taking full advantage of his Christian liberty was that [he] might win the more. He deeply believed that “he who is wise wins souls” (Prov. 11:30) and was willing to do anything and to sacrifice anything to win people to Jesus Christ. As far as his rights were concerned he was free from all men, but because of his love for all men he would gladly limit those rights for their sakes. He had, figuratively, become a slave to all. He would modify his habits, his preferences, his entire life–style if any of those things caused someone to stumble, to be offended, or to be hindered from faith in the Lord.

Again we are reminded that in the gray areas of living, those that involve practices about which the Bible does not speak, Paul, as all believers, was free to do as his conscience allowed. But love would not let him do anything that the consciences of weaker believers would not allow. Love would not even allow him to do things that would be offensive to unbelievers to whom he witnessed. He would put every questionable thing in his life under the control of love.

Under the Mosaic law every Hebrew who was enslaved by another Hebrew had to be offered his freedom after six years. But if he loved his master and preferred to remain in that household, he could become a permanent slave, and his ear was pierced as a sign of his voluntary enslavement (Ex. 21:2–6).

In a figurative way Paul made himself such a slave to other men. I have made myself a slave is only two words in Greek (edoulosa, “I enslave,” and emauton, “myself”). That word for enslavement is very strong. It is used to describe Israel’s 400–year experience in Egypt (Acts 7:6), the marriage bond (1 Cor. 7:15), addiction to wine (Titus 2:3), and the Christian’s new relationship to righteousness (Rom. 6:18). It was not a small or easy thing that Paul enslaved himself to all. But his Lord had taught that “whoever wishes to be first … shall be slave of all” (Mark 10:44).

Paul’s willing adjustment of his living in order to identify with those to whom he witnessed was part of what today we call preevangelism. What he did in this regard was not a part of the gospel; it had nothing to do with the gospel. But it helped many unbelievers to listen to the gospel and be more open to receive it.

To illustrate his voluntary slavery Paul mentions three ways in which he had adapted, and would continue to adapt, his living in order to help others be more receptive to Christ. Each of these illustrations, like the statement of the principle itself (v. 19), ends with a purpose clause (“that I might/may …”) indicating his great desire to win people to Christ.

To the Jews I became as a Jew. First, within scriptural limits he would be as Jewish as necessary when working with Jews. In Christ he was no longer bound to the ceremonies, rituals, and traditions of Judaism. Following or not following any of those things had no affect on his spiritual life. But if following them would open a door for his witnessing to Jews, he would gladly accommodate. What had once been legal restraints now had become love restraints. His motive was clearly to win Jews to salvation in Jesus Christ.

Speaking of his fellow Jews, Paul said, “My heart’s desire and my prayer to God for them is for their salvation” (Rom. 10:1). Even if preaching to the Gentiles caused some Jews to accept Christ out of jealousy, that would be good (11:14). Earlier in that same letter he said, “For I could wish that I myself were accursed, separated from Christ for the sake of my brethren, my kinsmen according to the flesh” (9:3).

If he was willing to do that for the sake of his fellow Jews, he could surely abide by their ceremonial regulations, observe a special day, or refrain from eating certain foods—if doing those things would help win those who are under the Law. When Paul wanted to take Timothy with him in his ministry he had him circumcised, “because of the Jews who were in those parts” where he intended to go (Acts 16:3). Timothy’s circumcision was of no benefit to him and certainly not to Paul. But it could be of great benefit to their ministry among Jews and was a small price for the prospect of winning some of them to the Lord.

At the advice of James and other leaders of the Jerusalem church, Paul willingly paid for and participated in a Jewish purification ceremony with four other Jewish Christians. He took part in the ritual in order to prove to the Jewish critics of Christianity that he was not teaching Jews to completely abandon Moses and the Old Testament law (Acts 21:20–26). The special Jewish vow Paul took in Cenchrea (Acts 18:18) may have been for the sake of some Jews.

Because Jews were still under the Law, Paul would himself act as under the Law when he worked among them. He did not believe, teach, or give the least suggestion that following the law was of any spiritual benefit. It could not gain or keep salvation, but it was a way of opening doors to work among the Jews.

To those who are without law, as without law. Second, Paul was willing to live like a Gentile when he worked among Gentiles.

To keep from being misunderstood, he makes it clear that he is not talking about ignoring or violating God’s moral law. The Ten Commandments and all of God’s other moral laws have, if anything, been strengthened under the New Covenant. For example, not only is it sin to commit murder but also to be inordinately angry with your brother or to call him a fool. Not only is adultery sinful, but so is lust (Matt. 5:21–30). Love does not abrogate God’s moral law but fulfills it (Rom. 13:8, 10; cf. Matt. 5:17). None of us in Christ is without [outside] the law of God, but rather are under the law of Christ. Every believer is under complete legal obligation to Jesus Christ—even though love, rather than the extemalities of the law, is to be the guiding force.

In other than moral matters, however, Paul identified as closely as possible with Gentile customs. He ate what they ate, went where they went, and dressed as they dressed. The purpose again was to win the Gentiles to Christ.

To the weak I became weak. Third, Paul was willing to identify with those, whether Jew or Gentile, who did not have the power of understanding to grasp the gospel. When among those who were weak he acted weak. He stooped to the level of their weakness of comprehension. To those who needed simple or repeated presentations, that is what he gave them. No doubt he demonstrated that kind of consideration in the case of the Corinthians themselves (cf. 2:1–5). His purpose was to win them to salvation.

In summary, Paul became all things to all men, that he might by all means save some. He did not compromise the gospel. He would not change the least truth in the least way in order to satisfy anyone. But he would condescend in any way for anyone if that would in any way help bring him to Christ. He would never set aside a truth of the gospel, but he would gladly restrict his liberty in the gospel. He would not offend Jew, Gentile, or those weak in understanding.

If a person is offended by God’s Word, that is his problem. If he is offended by biblical doctrine, standards, or church discipline, that is his problem. That person is offended by God. But if he is offended by our unnecessary behavior or practices—no matter how good and acceptable those may be in themselves—his problem becomes our problem. It is not a problem of law but a problem of love, and love always demands more than the law. “Whoever slaps you on your right cheek, turn to him the other also. And if anyone wants to sue you, and take your shirt, let him have your coat also. And whoever shall force you to go one mile, go with him two” (Matt. 5:39–41).

Paul’s life centered in living out the gospel and in preaching and teaching the gospel. Nothing else was of any concern to him. I do all things for the sake of the gospel. His life was the gospel. He therefore set aside anything that would hinder its power and effectiveness.

Fellow partaker (sunkoinonos) refers to joint participation, joint sharing. The idea here is that Paul wanted everyone else to be a fellow partaker with him in the benefits and blessing of the gospel. He wanted them to be with him in the family of God.