Necessity is the mother of all human actions.
(En. in ps. 83, 8)
Man himself, so much admired, is a great mystery.
(Sermo 126, 4)
In the material world, a foot is one thing, a ladder is another and wings still another. In the interior world, however, feet, ladders, and wings are the affections of a good will, with them, we walk, we climb, and we fly.
(En. in ps. 38, 2)