A proof that gratitude is desirable for itself lies in the fact that ingratitude is to be avoided for itself, because no vice more powerfully rends asunder and destroys the union of the human race. To what do we trust for safety, if not in mutual good offices one to another? It is by the interchange of benefits alone that we gain some measure of protection for our lives, and of safety against sudden disasters. Taken singly, what should we be? a prey and quarry for wild beasts, a luscious and easy banquet; for while all other animals have sufficient strength to protect themselves, and those which are born to a wandering solitary life are armed, man is covered by a soft skin, has no powerful teeth or claws with which to terrify other creatures, but weak and naked by himself is made strong by union.

God has bestowed upon him two gifts, reason and union, which raise him from weakness to the highest............