Thomas Aquinas,
Summa Theologiae — Question 87 - OF THE DEBT OF PUNISHMENT…
“ A satisfactory punishment is, in a way, voluntary. And since those who differ as to the debt of punishment, may be one in will by the union of love, it happens that one who has not sinned, bears willingly the punishment for another: thus even in human affairs we see men take the debts of another upon themselves. If, however, we speak of punishment simply, in respect of its being something penal, it has always a relation to a sin in the one punished. Sometimes this is a relation to actual sin, as when a man is punished by God or man for a sin committed by him. ”
