11 For the sake of all these things then, let us glorify Him, our Guardian; not only by words, but also by deeds; and let us show forth an excellent conversation, not only in general, but in particular with regard to abstinence from oaths. For not every sin brings the same penalty; but those which are easiest to be amended, bring upon us the greatest punishment: which indeed Solomon intimated, when he said, “It is not wonderful if any one be taken stealing; for he steals that he may satisfy his soul that is hungry; but the adulterer, by the lack of understanding, destroys his own soul.” But what he means is to this effect. The thief is a grievous offender, but not so grievous a one as the adulterer: for the former, though it be a sorry reason for his conduct, yet at the same time has to plead the necessity arising from indigence; but the latter, when no necessity compels him, by his mere madness rushes into the gulph of iniquity. This also may be said with regard to those who swear. For they have not any pretext to allege, but merely their contempt.
Source: Homilies on the Statues (New Advent)