1 Corinthians 9:19 states the overarching principle: Paul becomes a servant to all to win more — directly sets up verse 20.

Acts 16:3 shows Paul circumcising Timothy to avoid offense to Jews — a direct example of becoming a Jew to win Jews as stated in 9:20.

Acts 17:2 shows Paul's custom of reasoning in synagogues, a concrete example of becoming a Jew to win Jews.

Acts 17:3 details Paul explaining Christ from the Scriptures in the synagogue, directly illustrating his adaptive method to reach Jews.

Acts 18:18 shows Paul cutting his hair due to a vow, an instance of participating in Jewish practice to win those under the law.

Acts 21:20-26 has Paul undergoing purification to show he lives in observance of the law, a clear example of becoming as under the law.

Acts 21:24 shows Paul actually following Jewish purification customs — a concrete example of him becoming a Jew to win Jews.

Acts 21:26 continues the same episode — Paul participates in temple rites, directly applying the principle of becoming under the law.

Galatians 4:12 pleads 'become as I am, for I also have become as you' — mirrors Paul's principle of adaptation in 1 Cor 9:20.

Romans 10:1 expresses Paul's heart for Israel's salvation — the motive behind his becoming a Jew.

Galatians 2:3 shows Paul not imposing the law on Titus — contrasting his freedom while he becomes under law to win Jews.

Galatians 4:21 warns against desiring to be under the law, contrasting Paul's temporary accommodation for the sake of the gospel.

Romans 11:14 reveals Paul's tactic of making Jews jealous — another method to win them, complementing his adaptation.

Galatians 3:23 describes being 'under the law' as imprisonment before faith — clarifies the condition Paul voluntarily adopts.

Galatians 4:5 describes Christ redeeming those under the law, paralleling Paul's aim to win them by becoming like them.

Galatians 5:18 says those led by the Spirit are not under law, echoing Paul's own status and the goal for his converts.