Thomas Aquinas Summa Theologica – First Part of the Second Part – Question 111 Article 3
As grace is divided into operating and cooperating, with regard to its diverse effects, so also is it divided into prevenient and subsequent, howsoever we consider grace. Now there are five effects of grace in us: of these, the first is, to heal the soul; the second, to desire good; the third, to carry into effect the good proposed; the fourth, to persevere in good; the fifth, to reach glory. And hence grace, inasmuch as it causes the first effect in us, is called prevenient with respect to the second, and inasmuch as it causes the second, it is called subsequent with respect to the first effect. And as one effect is posterior to this effect, and prior to that, so may grace be called prevenient and subsequent on account of the same effect viewed relatively to divers others. And this is what Augustine says (De Natura et Gratia xxxi): “It is prevenient, inasmuch as it heals, and subsequent, inasmuch as, being healed, we are strengthened; it is prevenient, inasmuch as we are called, and subsequent, inasmuch as we are glorified.”
God’s love signifies something eternal; and hence can never be called anything but prevenient. But grace signifies a temporal effect, which can precede and follow another; and thus grace may be both prevenient and subsequent. The division into prevenient and subsequent grace does not divide grace in its essence, but only in its effects, as was already said of operating and cooperating grace.
