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).
From CONTRA GENTILES, BOOK ONE: GOD
by Thomas Aquinas (translated by Anton C. Pegis)