This epistle is really the chief part of the New Testament, and is truly the purest gospel. It is worthy not only that every Christian should know it word for word, by heart, but also that he should occupy himself with it every day, as the daily bread of the soul. We can never read it or ponder over it too much; for the more we deal with it, the more precious it becomes and the better it tastes.
Luther’s Works – Vol. 35: Word and Sacrament I (Philadelphia: Fortress Press, 1999), 365.