While reading Aquinas’ Summa Against Gentiles, I found this little gem in the very beginning of the work:
Now, the end of each thing is that which is intended by its first author or mover. But the first author and mover of the universe is an intellect, as will be later shown. The ultimate end of the universe must, therefore, be the good of an intellect. This good is truth. Truth must consequently be the ultimate end of the whole universe, and the consideration of the wise man aims principally at truth. So it is that, according to His own statement, divine Wisdom testifies that He has assumed flesh and come into the world in order to make the truth known: “For this was I born, and for this came I into the world, that I should give testimony to the truth” (John 18:37). The Philosopher himself establishes that first philosophy is the science of truth, not of any truth, but of that truth which is the origin of all truth, namely, which belongs to the first principle whereby all things are. The truth belonging to such a principle is, clearly, the source of all truth; for things have the same disposition in truth as in being.
It belongs to one and the same science, however, both to pursue one of two contraries and to oppose the other. Medicine, for example, seeks to effect health and to eliminate illness. Hence, just as it belongs to the wise man to meditate especially on the truth belonging to the first principle and to teach it to others, so it belongs to him to refute the opposing falsehood.
Appropriately, therefore, is the twofold office of the wise man shown from the mouth of Wisdom in our opening words: to meditate and speak forth of the divine truth, which is truth in person (Wisdom touches on this in the words my mouth shall meditate truth), and to refute the opposing error (which Wisdom touches on in the words and my lips shall hate impiety) [*]. By impiety is here meant falsehood against the divine truth. This falsehood is contrary to religion, which is likewise named piety. Hence, the falsehood contrary to it is called impiety.
— Aquinas, Summa Against Gentiles, I:i (Book I, translated by Anton C. Pegis; source)
[*] Note: Words in boldface within the quoted text are from Proverbs 8:7.