Catholics are often surprised to learn that there are Evangelical Protestants who claim to be Thomists. When I was a Protestant, I was one of them. What
attracts these Evangelicals are Thomas’s views on faith and reason, his philosophy of the human person, command of Scripture, and intellectual rigor. Some of them think that on justification, Thomas is closer to the Protestant Reformers than to the Catholic view (as taught in the 1994 Catechism of the Catholic Church). The late Presbyterian theologian John Gerstner, for instance, claimed that with St. Augustine, St. Thomas “taught the biblical doctrine of justification so that if the Roman Church had followed Aquinas the Reformation would not have been absolutely necessary.” Others have made similar arguments, but they are spectacularly wrong. As usual, it all hinges on understanding faith and works.
For St. Thomas, justification refers not only to entrance into the family of God at Baptism – administered for the remission of sins – but to the infusion of sanctifying grace at Baptism and all the subsequent graces that work to transform the Christian from the inside out. Consider, for instance, Aquinas’s explanation of sanctifying grace as habitual grace: “a double effect of grace, even as of every other form; the first of which is `being,’ and the second, `operation.’” For example, “the work of heat is to make its subject hot, and to give heat outwardly. And thus habitual grace, inasmuch as it heals and justifies the soul, or makes it pleasing to God, is called operating grace; but inasmuch as it is the principle of meritorious works, which spring from the free-will, it is called cooperating grace.”
Read the whole thing here.