Louis de Montfort points out that interior mortifications are more important than exterior ones, even though the latter are not to be disregarded. The conquest of selfishness, or self-will, is the greatest challenge. Even the good results of difficult practices of mortification may be spoiled by self-seeking. Hence he recommends that all exterior acts of mortification be done under obedience. “For exterior and voluntary mortification to be profitable, it must be accompanied by the mortifying of the judgment and the will through holy obedience, because without this obedience all mortification is spoiled by self will and often becomes more pleasing to the devil than to God” (LEW 201).
Montfort also teaches that little mortifications are often more meritorious than great ones because they are less apt to give rise to vanity. Small interior acts of mortification made for God, for example, repressing useless words and glances or checking a movement of anger or impatience, etc., could turn out to be great victories. In this connection, he specifically asks—in his down-to-earth language—to mortify “1) a certain natural activity that inclines you to hurry and to accomplish much; 2) changing moods that rule you and displease your neighbor; 3) your tongue, which always wishes to talk, laugh, mock etc.; 4) a tendency to lack religious modesty in your bearing, which makes you act like a child, laugh like a fool, jump around like a juggler, and eat and drink like an animal” (RW 176).
Special devotee of the Blessed Virgin Mary that he was, Montfort sees Mary as the best example of universal mortification. He lists mortification as one of her ten principal virtues, which should be imitated by those who are devoted to her. Acts of interior or exterior mortification may be performed as one of the five principal practices of true devotion to her (TD 108, 116).
Taken from: Jesus Living in Mary: Handbook of the Spirituality of St. Louis de Montfort(Litchfield, CT: Montfort Publications, 1994).