19 May there be then speedily some favourable and propitious change! This certainly I foretell and testify, that although this cloud should pass away, and we yet remain in the same condition of listlessness, we shall again have to suffer much heavier evils than those we are now dreading; for I do not so much fear the wrath of the Emperor, as your own listlessness. Surely it is not sufficient by way of apology that we supplicate two or three days, but it is necessary that we should make a change in our whole life, and that while abstaining from wickedness we should persevere continually in virtue.
For as those who are sickly, unless they keep up a constant regimen, would find no advantage by their observing a two or three days' discipline; so those who are in sin, if they do not exercise sobriety at all times, will find no benefit in two or three days' amendment. For as it is said, that he who is washed, and is again afterwards polluted with the mire, has gained nothing; so he who has repented for three days, and has again returned to his former state, has accomplished nothing.
Let us not therefore, now act as we have always done hitherto. For many times, when we have been surprised by earthquakes, as well as famine and drought, after becoming more sober and gentle for three or four days, we did but return again to the former course. For this cause our present troubles have happened. But if we have not done so before; yet, now at least let us all persevere in the same piety; let us preserve the same meekness, that we may not again need another stroke. Was not God able to have prevented what has taken place? He did, however, permit it, that He might make those who despised Him more sober-minded, through dread of a fellow-servant!
Source: Homilies on the Statues (New Advent)