"The gift of understanding"

"UNDERSTANDING implies an intimate knowledge, for "intelligere" [to understand] is the same as "intus legere" [to read inwardly]. This is clear to anyone who considers the difference between intellect and sense, because sensitive knowledge is concerned with external sensible qualities, whereas intellective knowledge penetrates into the very essence of a thing, because the object of the intellect is "what a thing is," as stated in De Anima iii, 6.

"Now there are many kinds of things that are hidden within, to find which human knowledge has to penetrate within so to speak. Thus, under the accidents lies hidden the nature of the substantial reality, under words lies hidden their meaning; under likenesses and figures the truth they denote lies hidden (because the intelligible world is enclosed within as compared with the sensible world, which is perceived externally), and effects lie hidden in their causes, and vice versa. Hence we may speak of understanding with regard to all these things.

"Since, however, human knowledge begins with the outside of things as it were, it is evident that the stronger the light of the understanding, the further can it penetrate into the heart of things. Now the natural light of our understanding is of finite power; wherefore it can reach to a certain fixed point. Consequently man needs a supernatural light in order to penetrate further still so as to know what it cannot know by its natural light: and this supernatural light which is bestowed on man is called the gift of understanding."

~St. Thomas Aquinas: ST, II-II, q. 8, a. 1.

St. Thomas Aquinas, by Fra Angelico.
Tempera on wood, 1340-45; Collezione Vittorio Cini, Venice.