Given the sin of impiety through which they [the Romans] sinned against the divine nature [by idolatry], the punishment that led them to sin against their own nature followed.... I say, therefore, that since they changed into lies [by idolatry] the truth about God, He brought them to ignominious passions, that is, to sins against nature; not that God led them to evil, but only that he abandoned them to evil.
Thomas AquinasLikewise grace and glory are referred to the same genus, since grace is nothing other than a certain first beginning of glory in us.
Thomas AquinasEvery 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 AquinasFuture contingents cannot be certain to us, because we know them as such. They can be certain only to God whose understanding is in eternity above time. Just as a man going along a road does not see those who come after him; but the man who sees the whole road from a height sees all those who are going along the road at the same time.
Thomas Aquinas