Epistle to the Galatians in Wikipedia

The Epistle of Paul to the Galatians, usually referred to simply as Galatians, is the ninth book of the New Testament. It is a letter from Paul of Tarsus to a number of Early Christian communities in the Roman province of Galatia in central Anatolia. The author is principally concerned with the controversy surrounding Gentile Christians and the Mosaic Law within Early Christianity, see also Paul of Tarsus and Judaism. Along with the Epistle to the Romans, it is the most theologically significant of the Pauline epistles, and has been particularly influential in Protestant thought...