Some say, How is it true that Christ says, “And with what measure ye shall mete it shall be measured to you again,” if temporal sin is to be punished by eternal suffering? They do not observe that it is not said “the same measure,” because of the equal space of time, but because of the equal retribution - namely, that he who has done evil should suffer evil, though even in that sense it might be said of that of which the Lord spoke here, namely of judgments and condemnations. Accordingly, he that judges and condemns unjustly, if he is judged and condemned, justly receives in the same measure though not the same thing that he gave; by judgment he did what was unjust, by judgment he suffers what is just.
Reproduced in full. Translation: Oxford 1841 (Newman), public domain (Public domain).
Also cites: City of God, xxi, 11