It is untrue that all knowledge can be shared with everyone, regardless of one’s preparation. Esotericism honors this fact.
Some spiritual teachings are made available only to initiates and only if these initiates have, as Jesus once said, “ears to hear.”
Initiates must purify their hearts in order that the ears of their hearts can be inclined toward the teachings. They must learn to be receptive, utterly.
To keep the teachings alive, then, some teachers mustn’t speak with outsiders about what cannot be understood and hence could, if they were spoken of in such contexts, lead to grave misunderstandings–or worse.
When teachings are indeed kept alive, then can they vibrate through students, disclosing truths that might just as well be called sacred.
It is the sacred that changes us.