Acts 16:3

Paul obviously did not circumcise Timothy because he believed that rite was necessary for his justification or sanctification (cf. 1 Corinthians 7:19). He did so because it was necessary for effective evangelistic ministry among Jews (cf. 1 Corinthians 9:20-22; Romans 14:13-15). Unbelieving Jews would not have given Paul a hearing if he had travelled with an uncircumcised Gentile even though Timothy was half Jewish (cf. 1 Corinthians 9:20). The Jews regarded an uncircumcised son of a Jewish mother to be an apostate Jew, a violator of the Mosaic Covenant. [Note: Bock, Acts, p. 523.] Paul was being culturally sensitive here.