Quoted to answer the objection that Paul was deceitful when he said he became 'as a Jew' or 'all things to all people'; the speaker used it to argue Paul was adapting his approach for evangelism, not lying or changing religions.
Scripture spotlight
1 Corinthians 9:18-23
bible
18 What then is my reward? That, when I preach the Gospel, I may present the Gospel of Christ without charge, so as not to abuse my authority in the Gospel. 19 For though I was free from all, I brought myself under bondage to all, that I might gain the more. 20 To the Jews I became as a Jew, that I might gain Jews; to those who are under the law, as under the law, that I might gain those who are under the law; 21 to those who are without law, as without law (not being without law toward God, but under law toward Christ), that I might win those who are without law. 22 To the weak I became as weak, that I might gain the weak. I have become all things to all men, that I may by all means save some. 23 Now I do this for the Gospel's sake, that I may be a joint partaker of it.