An epistle of St. Paul to the churches in Galatia, which was an especial favourite with Luther, as, with its doctrine of spiritual freedom in Christ, it might well be, for it corroborated the great revelation first made to him by a neighbour monk; "man is not saved by singing masses, but by the grace of God"; it is a didactic epistle, in assertion, on the one hand, of freedom from the law, and, on the other, of the power of the spirit.