Heidegger's Bible Handbook: Galatians: Occasion and Argument of the Epistle
3. The occasion and argument of the Epistle.
The occasion for writing the Epistle was furnished by the seduction of the Galatians, who, having been taken in by some disturbers, thought that circumcision was to be adjoined to the profession of the Christian name. Hence the Apostle, trying to reduce the seduced Galatians to the Royal way of truth, so urges upon them the truth of the Gospel and the preservation of Christian liberty, and at the same time ties to that Christian liberty an admonition, that they abuse it not unto fleshly liberty.