17 Thus did the barbarians! And are we not ashamed, and ought we not to hide our faces, while instead of changing our habits, as they did, we change only our habitations; privily removing our goods, and doing the deeds of men that are drunken? Our Master is angry with us; and we, neglecting to appease His wrath, carry about our household stuff from place to place, and run hither and there, seeking where we may deposit our substance; while we ought rather to seek where we may deposit our soul in safety; or rather, it behooves us not to seek, but to entrust its safety to virtue and uprightness of life.
For when we were angry and displeased with a servant, if he, instead of defending himself against our displeasure, went down to his apartment, and collecting together his clothes, and binding up together all his movables, meditated a flight, we could not tamely put up with this contempt. Let us then desist from this unseasonable endeavour, and let us each say to God, “Whither shall I go from Your Spirit, and whither shall I flee from Your presence?” Let us imitate the spiritual wisdom of the barbarians.
They repented even on uncertain grounds! For the sentence had no such clause, “If you turn and repent, I will set up the city;” but simply, “Yet three days, and Nineveh shall be overthrown.” What then said they? “Who knows whether God will repent of the evil He said He would do unto us?” Who knows? They know not the end of the event, and yet they do not neglect repentance! They are unacquainted with God's method of showing mercy, and yet they change upon the strength of uncertainties!
For neither was it in their power to look at other Ninevites who had repented and been saved; nor had they read prophets; nor had they heard patriarchs; nor had they enjoyed counsel, or partaken of admonition; nor had they persuaded themselves that they should certainly propitiate God by repentance. For the threatening did not imply this: but they were doubtful, and hesitating concerning it; and yet they repented with all diligence. What reason then shall we have to urge, when those, who had no ground for confidence as to the issue, are seen to have exhibited so great a change; but thou who hast ground of confidence in the mercy of God, and who hast frequently received many pledges of His care, and hast heard prophets, and apostles, and hast been instructed by actual events; hast yet no emulation to reach the same measure of virtue as these did!
Great assuredly was their virtue! But greater by far was the mercy of God! And this may be seen from the very greatness of the threat. For this reason God did not add to the declaration, “But if you repent. I will spare:” in order that by setting forth a sentence without limitation, He might increase the fear and having increased the fear, He might constrain them more speedily to repentance.
Source: Homilies on the Statues (New Advent)