Ravens refuse to feed their young until their feathers grow and become black, and the parents can recognize them as their own. Before the young have feathers, they feed on dew. When a raven eats a corpse, it first pecks out the eyes so that it can reach the brain.

As the raven first pecks out the eyes, so the devil first destroys the ability to judge correctly, leaving the mind open to attack. As the raven will not feed the chicks until it recognizes them as its own, so the teacher should not tell his students of the inner mysteries until he recognizes that they are ready to receive them, when they have grown dark with repentance.