The Philosophy of the Upanishads c5.s3.23

c5.s3.23

Ait. Ār. 3. 2. 6. 9 :—"These combinations of letters (according to their secret meaning, their *upanishad*) the teacher shall not impart to anyone who is not his immediate pupil (*antevâsin*), who has not already lived for a year in his house, who does not himself intend to be a teacher."