5 For besides the subjects which have been mentioned, there is another, about which some are no less perplexed, enquiring within themselves on what account God permitted a man possessing such confidence towards Him, whose bones and relics expelled demons, to fall into such a state of infirmity; for it is not merely that he was sick, but constantly, and for a length of time; and by these recurring and prolonged infirmities he was not permitted to have even a brief respite. “How does this appear,” it may be asked? From the very words of Paul, for he does not say, on account of the “infirmity,” but on account of the “infirmities;” and not merely “infirmities,” but he clearly speaks of these as being constant, when he says “your frequent infirmities.” Let those then attend to this, whoever they are, who being given over to a lingering sickness are querulous and dejected under it.
Source: Homilies on the Statues (New Advent)