1 Corinthians 9:22

To the weak I became weak, that I might gain the weak: I am become all things to all men, that I may by all means save some.

David Lipscomb's comment on this is:

Paul accommodated himself to the prejudices and preferences of men so far as he could without sacrificing truth and righteousness, in order to win them to Christ ... He did this not that he might be personally popular with any man, but that by doing so he might throw no obstacle in the way of their giving the gospel a fair hearing.[16]

For example, Paul felt no obligation whatever to keep the forms and ceremonies of the law of Moses; yet he observed and kept such things in circumstances where his failure to do it would have antagonized the Jews, and in cases where their observance did not violate the spirit of the new law in Christ Jesus. Thus, Paul shaved his head; but there is no record that he ever ate the Jewish Passover. As he said, "Christ is our Passover."

That I may save some ... As Johnson said, "This does not remove salvation from the hands of God";[17] and, when it is declared in the word of the Lord that people should "save themselves" (Acts 2:40), it is likewise true that their doing so cannot remove salvation from God's hands. When a man is baptized unto the remission of his sins, it does not make him his own saviour; because, when one obeys the gospel, he saves himself in the sense that he does that without which not even God can save him. In that same sense, not even God could save sinners without the preaching of the word; and by preaching the word, Paul, in that sense, saved people.

[16] David Lipscomb, Commentary on First Corinthians (Nashville: Gospel Advocate Company, 1935), p. 137.

[17] S. Lewis Johnson, Jr., op. cit., p. 616.