‘Ipse enim dixit, solum unum necessarium, nempe verbum Idei in quo vivit homo’ (Luke 10.42). One thing alone is essential, namely, the Word of God by which man lives. These words could be put as a motto to Luther's entire theology. For the Roman Catholic the sacrifice of the Mass is supreme and absolutely essential for salvation. In Luther the Word occupies this place, and he rejects the sacrifice of the Mass. It is not the Eucharist but the Word which stands in the centre of his theology; the Word has been given for man's salvation, and every-thing is subordinate to it.