Teaching (n.) has here its craftsman and here its material, and the matter is wholly in our control: so what is lacking?
Teaching (n.) that withholds the hurtful truth is cruelty: leave the pupil unreformed and one day he will blame you for having said nothing.
Teaching (n.) by someone with no calling profanes the Mysteries: copying the hierophant's words without his purity, age or robe, as if the words were sacred in themselves.
Teaching (n.) without the right life is vulgarizing the Mysteries: copy the chapel, the hierophant, the torches, the words — and still nothing holy happens.
Teaching (n.) needs a foothold in the pupil: you can redirect a young man who already loves beauty, but go and persuade a pig not to roll in the mud.