The sick are to be admonished to consider how great health of the heart is in bodily affliction, which recalls the mind to knowledge of itself, and renews the memory of infirmity which health for the most part casts away, so that the spirit, which is carried out of itself into elation, may be reminded by the smitten flesh from which it suffers to what condition it is subject. Which thing is rightly signified to Balaam (had he but been willing to follow obediently the voice of God) in the very retardation of his journey. For Balaam is on his way to attain his purpose; but the animal which is under him thwarts his desire. The ass, stopped by the prohibition, sees an angel which the human mind sees not; because for the most part the flesh, slow through afflictions, indicates to the mind from the scourge which it endures the God whom the mind itself which has the flesh under it did not see, in such sort as to impede the eagerness of the spirit which desires to advance in this world as though proceeding on a journey, until it makes known to it the invisible one who stands in its way. Whence also it is well said through Peter, He had the dumb beast of burden for a rebuke of his madness, which speaking with a man's voice forbade the foolishness of the prophet. For indeed a man is rebuked as mad by a dumb beast of burden, when an elated mind is reminded by the afflicted flesh of the good of humility which it ought to retain. But Balaam did not obtain the benefit of this rebuke for this reason, that, going to curse, he changed his voice, but not his mind. The sick are to be admonished to consider how great a boon is bodily affliction, which both washes away committed sins and restrains those which might have been committed, which inflicts on the troubled mind wounds of penitence derived from outward stripes. Whence it is written, The blueness of a wound cleanses away evil, and stripes in the secret parts of the belly. For the blueness of a wound cleanses away evil, because the pain of scourges cleanses iniquities, whether meditated or perpetrated. But by the appellation of belly the mind is wont to be understood. For that the mind is called the belly is taught by that sentence in which it is written, The spirit of man is the lamp of the Lord, which searches all the secret parts of the belly. As if to say, The illumination of Divine inspiration, when it comes into a man's mind, shows it to itself by illuminating it, whereas before the coming of the Holy Spirit it both could entertain bad thoughts and knew not how to estimate them. Then, the blueness of a wound cleanses away evil, and stripes in the secret parts of the belly, because when we are smitten outwardly, we are recalled, silent and afflicted, to memory of our sins, and bring back before our eyes all our past evil deeds, and through what we suffer outwardly we grieve inwardly the more for what we have done. Whence it comes to pass that in the midst of open wounds of the body the secret stripe in the belly cleanses us more fully, because a hidden wound of sorrow heals the iniquities of evil-doing.
The sick are to be admonished, to the end that they may keep the virtue of patience, to consider incessantly how great evils our Redeemer endured from those whom He had created; that He bore so many vile insults of reproach; that, while daily snatching the souls of captives from the hand of the old enemy, He took blows on the face from insulting men; that, while washing us with the water of salvation, He hid not His face from the spittings of the faithless; that, while delivering us by His advocacy from eternal punishments, He bore scourges in silence; that, while giving to us everlasting honours among the choirs of angels, He endured buffets; that, while saving us from the prickings of our sins, He refused not to submit His head to thorns; that, while inebriating us with eternal sweetness, He accepted in His thirst the bitterness of gall; that He Who for us adored the Father though equal to Him in Godhead, when adored in mockery held His peace: that, while preparing life for the dead, He Who was Himself the life came even unto death. Why, then, is it thought hard that man should endure scourges from God for evil-doing, if God underwent so great evils for well-doing? Or who with sound understanding can be ungrateful for being himself smitten, when even He Who lived here without sin went not hence without a scourge?
Source: Pastoral Rule (New Advent)