Those who are dissatisfied with the fact that the good receive evil, and the evil good, are shown by the example of Lazarus, and on the authority of Paul, that punishments and rewards are reserved for a future life.
57. We have fully discussed two questions; and this discussion, as we think, has not turned out quite unfavourably for us. A third question yet remains; it is this: Why do sinners have abundance of wealth and riches, and fare sumptuously, and have no grief or sorrow; while the upright are in want, and are punished by the loss of wives or children? Now, that parable in the Gospel ought to satisfy persons like these; for the rich man was clothed in purple and fine linen, and dined sumptuously every day; but the beggar, full of sores, used to gather the crumbs of his table. After the death of the two, however, the beggar was in Abraham's bosom in rest; the rich man was in torment. Is it not plain from this that rewards and punishments according to deserts await one after death?
58. And surely this is but right. For in a contest there is much labour needed— and after the contest victory falls to some, to others disgrace. Is the palm ever given or the crown granted before the course is finished? Paul writes well; He says: “I have fought a good fight, I have finished my course, I have kept the faith; henceforth there is laid up for me a crown of righteousness, which the Lord, the righteous judge, shall give me at that day; and not to me only, but unto all them also that love His appearing.” “In that day,” he says, He will give it— not here. Here he fought, in labours, in dangers, in shipwrecks, like a good wrestler; for he knew how that “through much tribulation we must enter into the kingdom of God.” Therefore no one can receive a reward, unless he has striven lawfully; nor is the victory a glorious one, unless the contest also has been toilsome.
Source: On the Duties of the Clergy (New Advent)