For our inner eyes to be blind is not to understand. That those eyes may be opened and see more and more clearly, hearts are cleansed by faith (see Acts 15:9). For, although no one can believe in God unless he understands something, still the very faith by which he believes heals him so that he may understand even more broadly, Some things we don’t believe unless we understand them; other things we don’t understand unless we believe them. For since faith comes from hearing, and hearing through the word of Christ (Rom 10:17), how can anyone believe a preacher if he doesn’t at least understand the language the preacher is speaking, not to mention other things? But if there were not some other things that we can’t understand unless we believe them, the prophet would not have said, “Unless you believe, you will not understand” (Is 7:9; LXX). Our minds advance toward an understanding of the things we believe, and our faith advances toward believing the things it understands, and by greater and greater understanding of these things, our minds make progress.
This does not happen by our own natural abilities, but by God’s help and gift; it happens as if by medicine and not by nature, as when a damaged eye receives the ability to see. One who says to God, then, “Give me understanding so that I may learn your commandments” (Ps 118:73) is not like a beast, entirely without understanding, nor should he, although a human being, be ranked with those who “walk in the vanity of their mind, having their understanding darkened, foreign to the way of God” (Eph 4:17-18). If he were that sort of person, he would not make that prayer. It’s no small insight to know from whom to ask for insight. (EnPs 118/18, 3; PL 37, 1552)
I love that last sentence! From whom do we learn? From infancy we learn from parents and families, of course, and we don’t have much choice initially but to trust what they say. Later there are our teachers and, later still, our professors, and if we might be inclined to trust the former in our early education, we are more likely to question the latter. But still, when you think about it, most of what rattles around in our minds and claims to be knowledge of “the real world” is things we trust because someone else has told us of their experience, or shared their insights or the conclusions they’ve verified. Sometimes growing up means recognizing that we trusted the wrong people, people who shouldn’t have been trusted, in general or in specific areas, and then it becomes important to learn from whom we might expect genuine, verifiable insights. Since most of our so-called “knowledge” in fact is believing, it is important to know from whom we can safely expect valid insights. This holds not only in matters of religion but throughout the range of human inquiry.