Martin Luther's favorite book, it is said, was Paul's Epistle to the Galatians, because it laid out so clearly the essential doctrine of Christianity, Justification by Faith - Alone! His commentary was transcribed from lectures - in 1531 and in Latin - to his students, quickly translated into the vernacular (German) and, by Theodore Graebner, into mid-twentieth century American English, with KJV scripture. The original Latin text, a compressed language, was translated to a full-length vernacular edition; this is the shorter version (260 pages).
I was amazed again and again that there is no redundancy here, in a lengthy review of six short chapters of the Greek epistle. Luther examines the letter as if he were holding a jewel up to the light and using every viewpoint. He tells us that the false teachers, who opposed Paul's doctrine with the Galatians, were undoubtedly well-spoken, well-educated men, something approaching an angel of light, but false teachers they were and for that, accursed. Particularly in his expatiation on this topic in the third chapter, Luther achieves deep spirituality and a pastoral comforting of tortured consciences, and opens this up for the reader - you share his, and Paul's, vehemence. The remainder of the epistle sees Paul's re-establishment of Christian cordiality with the Galatians, still using every means possible to encourage their loyalty to this essential doctrine.
Interspersed among the commentary by Luther are short observations by Dr Jackson on the modern heresies and misjudgments which are new challenges - particularly "objective justification" and Church Growth. No mincing of words in either author of the commentaries! You may have read the Small Catechism and the Augsburg Confession. This should be next on your reading list.