Galatians 5:2

If you converted from heathenism be circumcised, it must be by believing and professing it necessary, which is false doctrine, and the Christ will profit you nothing: not that the practice of those ceremonies was at the time sinful, especially for those that had been Jews, but it was an error to judge them necessary for converted Gentiles. Besides, he that judges circumcision necessary, must also judge himself bound to keep all the other ceremonies and precepts of the law. (Witham)