Every judgement of conscience, be it right or wrong, be it about things evil in themselves or morally indifferent, is obligatory, in such wise that he who acts against his conscience always sins.
Thomas AquinasIt is not theft, properly speaking, to take secretly and use another's property in a case of extreme need: because that which he takes for the support of his life becomes his own property by reason of that need
Thomas AquinasPeace is the work of justice indirectly, in so far as justice removes the obstacles to peace; but it is the work of charity (love) directly, since charity, according to its very notion, causes peace.
Thomas AquinasThe magnitude of the punishment matches the magnitude of the sin. Now a sin that is against God is infinite; the higher the person against whom it is committed, the graver the sin-it is more criminal to strike a head of state than a private citizen-and God is of infinite greatness. Therefore an infinite punishment is deserved for a sin committed against Him.
Thomas Aquinas