The knowledge that is faith and its objects must come from above. This isn’t just faith in God, but in all unprovable matters in which there is absolute assurance.
1 Now, as a result of divine grace causing charity in us, it is also necessary for faith to be caused in us by grace.
2 Indeed, the movement whereby we are directed by grace to our ultimate end is voluntary, not violent, as we showed above. Now, there cannot be a voluntary movement toward something unless it is known. So, the knowledge of the ultimate end must be accorded us by grace, so that we may be voluntarily directed to it. But this knowledge cannot be by means of open vision in this life, as we showed above. Therefore, this knowledge must be through faith.
3 Again, in every knowing being the mode of knowledge depends on the mode of its proper nature; hence, the mode of knowing is different for an angel, a man, and a brute animal, inasmuch as their natures are different, as is clear from things said earlier.
But to man, in order that he may attain his ultimate end, there is added a perfection higher than his own nature, namely, grace, as we have shown. Therefore, it is necessary that, above man’s natural knowledge, there also be added to him a knowledge which surpasses natural reason. And this is the knowledge of faith, which is of the things that are not seen by natural reason.
4 Besides, whenever something is moved by an agent to what is proper to the agent, the thing moved must be, at the start, imperfectly subject to the impulsions of the agent, impulsions that remain somewhat foreign and improper to it, until at the end of the movement they do become proper to it. For example, wood is first heated by fire, and that heat does not belong to the wood but is apart from its nature; at the end, however, when the wood is now ignited, the heat becomes proper and connatural to it.
Likewise, when a person is being taught by a teacher, he must at the start accept the teacher’s conceptions, not as one who understands them by himself, but by way of belief, as things which are beyond his capacity; but at the end, when he has become learned, he can understand them.
Now, as is clear from what we have said, we are directed by the help of divine grace to our ultimate end. But the ultimate end is an open vision of the First Truth in Itself, as we showed above. Therefore, before it comes to this end, man’s intellect must be subject to God by way of belief, under the influence of divine grace which accomplishes this.
Notes This is no small things, and comes to us in many forms. For example, axioms in logic and math. But also in all of the tools of reason, the way to argue, which we know are true only based on faith.
5 Moreover, at the beginning of this work we indicated the advantages which made it necessary for divine truth to be offered to men by way of belief. It is also possible to conclude from these reasons that it was necessary for faith to be a product in us of divine grace.
6 Hence, the Apostle says to the Ephesians (2:8): “by grace you are saved through faith; and that not of yourselves, for it is the gift of God.”
7 By this conclusion we set aside the error of the Pelagians, who said that the beginning of faith in us was not from God but from ourselves.