Here the Redemptorist Father Peter Geiermann discusses the importance of bringing the five external senses under the control of reason. He writes: “By following their senses instead of regulating their conduct according to the word of God, our first parents lost happiness and brought sin and misery into the world. In consequence of their sensuality human nature inclines to evil, the world allures to sin, and Satan has grown astute in tempting mankind. Before us stand the tree of life and the tree of the knowledge of good and evil. The spirit inclines to the former, the flesh to the latter. As we obtain knowledge primarily through the senses, St. Augustine aptly calls them ‘the doors by which life and death enter the soul.’ If we do not wish death to enter our souls through the senses we must keep them so completely under the control of reason enlightened by faith that we can turn them instinctively from any unforeseen danger and concentrate them on what is conducive to life eternal. This subjugation of the senses, says Thomas a Kempis, purifies the heart, gives peace to the soul, and inclines the will to devotion.”
Concerning the sense of sight, Father Geiermann writes: “The most numerous and the most lasting impressions made on the soul usually enter through the sense of sight. To cultivate purity of heart it will therefore be necessary to exercise specially custody of the eyes. Without doing anything extravagant or ridiculous this can easily be accomplished by those who keep the Christian ideal constantly before their minds and are determined to attain it in their daily lives. In all things let them (1) act from principle and guard against natural impulse; (2) watch and pray that they may enjoy the special protection of Divine Providence; (3) conquer fickleness of heart by cultivating a tender conscience; (4) not fix their gaze on a person of the opposite sex that might easily incite them to impure thoughts or desires; (5) avoid suggestive books, pictures, and plays; (6) guard against idle curiosity; and (7) by the contemplation of the beauties of nature learn to raise their minds and hearts to God.”
Quotations from Peter Geiermann, The Narrow Way (New York: Benziger, 1914).