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
[of the rich man and Lazarus] ought to satisfy…
Is it not plain from this that rewards and punishments according to deserts await one after death?
And surely this is right. For in a contest there is much labor 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 the good fight, I have finished the race, I have kept the faith.
Finally, there is laid up for me the crown of righteousness, which the Lord, the righteous Judge,
will give to me on that Day,
and not to me only but also to all who have loved His appearing.”
In that day, he says, He will give it – not here.
Here he fought, in labors, in dangers, in shipwrecks, like a good wrestler;
for he knew how that through much tribulation we must enter into the kingdom of God 
(Acts 14:22).
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.
St. Ambrose