The beauty of wisdom is made plain by the divine testimony. From this he goes on to prove its connection with the other virtues.
64. Is there any one who would like to be beautiful in face and at the same time to have its charm spoilt by a beast-like body and fearful talons? Now the form of virtues is so wonderful and glorious, and especially the beauty of wisdom, as the whole of the Scriptures tell us. For it is more brilliant than the sun, and when compared with the stars far outshines any constellation. Night takes their light away in its train, but wickedness cannot overcome wisdom.
65. We have spoken of its beauty, and proved it by the witness of Scripture. It remains to show on the authority of Scripture that there can be no fellowship between it and vice, but that it has an inseparable union with the rest of the virtues. “It has a spirit sagacious, undefiled, sure, holy, loving what is good, quick, that never forbids a kindness, kind, steadfast, free from care, having all power, overseeing all things.” And again: “She teaches temperance and justice and virtue.”
Source: On the Duties of the Clergy (New Advent)