In the same interest, _viz._, to enrich the brief text of the Catechism and, as it were, quicken it with concrete perceptions, Luther urged the use of Bible-stories as illustrations. For the same reason he added pictures to both of his Catechisms. His _Prayer-Booklet_ contained as its most important part the text and explanation of the Catechism and, in addition, the passional booklet, a sort of Bible History. To this Luther remarks: "I considered it wise to add the ancient passional booklet [augmented by Luther] to the Prayer-Booklet, chiefly for the sake of the children and the unlearned, who are more apt to remember the divine histories if pictures and parables are added, than by mere words and teaching, as St. Mark testifies, that for the sake of the simple Christ, too, preached to them only in parables." (W. 10, 2, 458.) Indeed, Luther left no stone unturned to have his instruction understood. On words and formulas, merely memorized, but not appropriated intellectually, he placed but little value. Memorizing, too, was regarded by Luther not as an end in itself, but as a means to an end. It was to serve the explanation and understanding. And its importance in this respect was realized by Luther much more clearly than by his modern critics. For when the text is safely embedded, as it were, in the memory, its explanation is facilitated, and the process of mental assimilation may proceed all the more readily. In this point, too, the strictures of modern pedagogs on Luther's Catechism are therefore unwarranted. Where Luther's instructions are followed, the memory is not overtaxed, and the understanding not neglected. The instruction advocated by Luther differed fundamentally from the mechanical methods of the Middle Ages. He insisted on a thorough mental elaboration, by means of sermons, explanations, questions and answers, of the material memorized, in order to elevate it to the plane of knowledge. With Luther we meet the questions: "What does this mean? What does this signify? Where is this written? What does it profit?" He engages the intellect. The _Table of Christian Life_ of the Middle Ages, which "all good Christians are in duty bound to have in their houses, for themselves, their children, and household," is regarded by Cohrs as a sort of forerunner of Luther's Small Catechism. "At the same time, however," Cohrs adds, "it clearly shows the difference between the demands made by the Church of the Middle Ages and the requirements of the Evangelical Church; yonder, numerous parts without any word of explanation, sacred formulas, which many prayed without an inkling of the meaning; here, the five chief parts, in which the emphasis is put on 'What does this mean?'" (Herzog, _R._ 10, 138.)