1 Corinthians 9:20 (ESV)

20 To the Jews I became as a Jew, in order to win Jews. To those under the law I became as one under the law (though not being myself under the law) that I might win those under the law.

The first group of people to whom Paul had made himself a servant was the unbelieving Jews. When among them, he acted as one under the law, despite his conviction that the ceremonial law had been abolished in Christ (Ephesians 2:15). He did not want to offend them unnecessarily, since it was his aim to win them.

As an example, we can think of Paul’s act of circumcising Timothy, when it was agreed that Timothy would accompany him on his missionary journeys. He did this because of the Jews who were in those places, for they all knew that his [Timothy’s] father was a Greek (Acts 16:3).

Paul accommodated himself to others not because he sought their approval, but because he sought their salvation (Galatians 1:10; 1 Thessalonians 2:4). Whenever people inside the church insisted on circumcision and the ceremonial law, he held his ground against them. He would not allow legalism to displace the gospel (Galatians 1:1 – 2:21; Colossians 2:16).