Thomas Aquinas

“ Therefore pusillanimity is opposed to magnanimity.
I answer that, Pusillanimity may be considered in three ways. First, in itself; and thus it is evident that by its very nature it is opposed to magnanimity, from which it differs as great and little differ in connection with the same subject. For just as the magnanimous man tends to great things out of greatness of soul, so the pusillanimous man shrinks from great things out of littleness of soul. ”

“ I answer that, Whatever is contrary to a natural inclination is a sin, because it is contrary to a law of nature. Now everything has a natural inclination to accomplish an action that is commensurate with its power: as is evident in all natural things, whether animate or inanimate. Now just as presumption makes a man exceed what is proportionate to his power, by striving to do more than he can, so pusillanimity makes a man fall short of what is proportionate to his power, by refusing to tend to that which is commensurate thereto. Wherefore as presumption is a sin, so is pusillanimity. ”

“ But pusillanimity does not proceed from pride, since the proud man sets himself above what he is, while the fainthearted man withdraws from the things he is worthy of. Therefore pusillanimity is not a sin. ”