“There is no more effective means of keeping the mind fresh and its faculties at the height of their performance than the occupation, within proper limitations, with some side-line of study. When we inquire how it is that some men maintain even into old age a peculiar freshness of mind and true balance of mental faculties, here is the answer.”

From: Graebner, Theodore. The Pastor as Student and Literary Worker: Lectures Delivered at Concordia Seminary, St. Louis. Second, revised edition. St. Louis : Concordia Publishing House, 1925, page 68.