Read 1 Corinthians 9 at Bible Gateway.
“For though I am free from all men, I have made myself a servant 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, that I might win those who are under the law; to those who are without law, as without law (not being without law toward God, but under the law toward Christ), that I might win those who arewithout law; to the weak I became as weak, that I might win the weak. I have become all things to allmen, that I might by all means save some. Now this I do for the gospel’s sake, that I may be partaker of it with you.” 1 Cor 9:19-23
What does Paul mean when he says, “under the law,” “without law,” and “under the law toward Christ”? Paul uses the phrase “under the law” in a few other places in his letters:
“Now we know that whatever the law says, it says to those who are under the law, that every mouth may be stopped, and all the world may become guilty before God.” Rom 3:19
“For sin shall not have dominion over you, for you are not under law but under grace. What then? Shall we sin because we are not under law but under grace? Certainly not!” Rom 6:14-15
In Rom 3 and 6, and in all the beginning chapters of Romans, Paul is establishing that every man, because he has been born of the seed of Adam, is under the dominion of sin. Because this is so, no man, by obeying the law, can be counted as righteous before God. Those who seek to establish their own righteousness by obeying the law, are under the law – they are under the requirement of the law for justification – which is perfect obedience in every point! To be under the requirement of the law for justification is to be under the dominion of sin and death!
But those who have been born of the Seed of the woman, who is Jesus Christ, receive the righteousness which is imparted to us by God, by faith, and are under grace – they have been justified before God by faith. To be under grace is to be under the dominion of righteousness and life!
“But before faith came, we were kept under guard by the law, kept for the faith which would afterward be revealed.” Gal 3:23
“But when the fullness of the time had come, God sent forth His Son, born of a woman, born under the law, to redeem those who were under the law, that we might receive the adoption as sons.” Gal 4:4-5
“Tell me, you who desire to be under the law, do you not hear the law?” Gal 4:21
“But if you are led by the Spirit, you are not under the law.” Gal 5:18
1 Corinthians 9:19
We see if we read Galatians in its entirety, that Paul’s topic is the same as in Romans – what justifies a man? From whence does he get his righteousness so that he is saved? Is it by obeying the law, so that righteousness is earned? Or is it by faith in Jesus Christ, so that righteousness is a free gift by grace? Those who are under the law in Galatians, are the same as those who are under the law in Romans – those who seek to be justified by their obedience to the law, rather than by faith in Jesus Christ!
So back to 1 Cor 9: when Paul says that he became as one under the law, so that he might win those who are under the law, he is saying that he became as one who sought righteousness by obedience to the law. He became as a Pharisee, so that he might win Pharisees.
When he says that he became as one without law, so that he might win those who are without law, he is talking about the Gentiles, who are without the Torah – they do not even know what the definition of righteousness and sin is according to God! So he did not act as a Pharisee around them, but as a Gentile. But then, lest we misunderstand him, he clarifies his meaning:
“… not being without law toward God, but under the law toward Christ …” 1 Cor 9:21
He did not abandon his obedience to God, since God has, by the Law, defined for us what obedience to Him looks like, what righteous behavior and unrighteous behavior is. In order to win Gentiles, he did not begin worshiping at temples, or working on Sabbath, or lying, or cheating, or any of those things that are lawless. He was not without law toward God. But he continued under the law toward Christ. He continued obeying the law of God.
He added the phrase, toward God, and toward Christ, so that we would distinguish his meaning, for he has used the phrase “under the law” before, and it means something specific, we saw, when he uses it. It is shorthand for being under the righteous requirement of the law for justification. It is shorthand for earning right standing by works of obedience to the law. But so that we know that he did not mean that he stopped obeying the law just because he has come among the Gentiles and has become as a Gentile in order to win Gentiles, he says he was under the law toward Christ. Jesus said, the one who loves Him, keeps His commandments (Joh 14:15)! Paul was obedient to the law toward Christ, only he was not obedient to gain right standing, but he was still obedient!