Aristotle, Nicomachean Ethics
H. Rackham, Ed.

[4] For friendship exacts what is possible, not what is due; requital in accordance with desert is in fact sometimes impossible, for instance in honoring the gods, or one's parents: no one could ever render them the honor they deserve, and a man is deemed virtuous if he pays them all the regard that he can. Hence it would appear that a son never ought to disown his father, although a father may disown his son; for a debtor ought to pay what he owes, but nothing that a son can do comes up to the benefits he has received, so that a son is always in his father's debt. But a creditor may discharge his debtor, and therefore a father may disown his son. At the same time, no doubt it is unlikely that a father ever would abandon a son unless the son were excessively vicious; for natural affection apart, it is not in human nature to reject the assistance that a son will be able to render. Whereas a bad son will look on the duty of supporting his father as one to be avoided, or at all events not eagerly undertaken; for most people wish to receive benefits, but avoid bestowing them as unprofitable.

So much then for a discussion of these subjects.