Acts 16
Then he came to Derbe and Lystra. And behold, a certain disciple was there, named Timothy, the son of a certain Jewish woman who believed, but his father was Greek. 2 He was well spoken of by the brethren who were at Lystra and Iconium. 3 Paul wanted to have him go on with him. And he took him and circumcised him because of the Jews who were in that region, for they all knew that his father was Greek.

So Paul in an effort to avoid any argument with the Jews who knew Timothy’s father was a Greek, circumcised Timothy. This is very interesting. Going out of your way to avoid the arguments, including doing something VERY painful.

I might NOT have gone with Paul if circumcision was necessary.

 

Here is a VERY good read: https://www.desiringgod.org/articles/why-was-timothy-circumcised