Basil of Caesarea

If the love of children for their parents is a natural endowment and if this love is noticeable in the behavior even of brute beasts, as well as in the affection of human beings in early infancy for their mothers, let us not appear to be less rational than infants or more savage than wild beasts by alienating ourselves from him who made us by being unloving toward him.… This gratitude is characteristic not only of humans, but it is also felt by almost all animals, so that they attach themselves to those who have conferred some good upon them.