Let us not avoid discourses concerning hell, that we may avoid hell. Let us not banish the remembrance of punishment, that we may escape punishment. If the rich man had reflected upon that fire, he would not have sinned; but because he never was mindful of it, therefore he fell into it. Tell me, O man, being about to stand before the Judgment-seat of Christ, do you speak of all things rather than of that? And when you have a matter before a judge, often only relating to words, neither day nor night, at no time or season do you talk of anything else, but always of that business, and when you are about to give an account of your whole life, and to submit to a trial, can you not bear even with others reminding you of that Judgment?
For this reason therefore all things are ruined and undone, because when we are about to stand before a human tribunal concerning matters of this life, we move everything, we solicit all men, we are constantly anxious about it, we do everything for the sake of it: but when we are about, after no long time, to come before the Judgment-seat of Christ, we do nothing either by ourselves, or by others; we do not entreat the Judge. And yet He grants to us a long season of forbearance, and does not snatch us away in the midst of our sins, but permits us to put them off, and that Goodness and Lovingkindness leaves nothing undone of all that belongs to Himself.
But all is of no avail; on this account the punishment will be the heavier. But God forbid it should be so! Wherefore, I beseech you, let us even if but now become watchful. Let us keep hell before our eyes. Let us consider that inexorable Account, that, thinking of those things, we may both avoid vice, and choose virtue, and may be able to obtain the blessings promised to those who love Him, by the grace and lovingkindness, etc.
Source: Homilies on Second Thessalonians (New Advent)