"Another point with regard to mantras which is stressed in the Indian books is that students are forbidden to use them in the presence of coarse or evil-minded people, because the power of a mantra will often intensity evil as well as good. If there were a person present who could not answer to the vibrations in their higher form, he might well received a lower octave, which would be quite likely to strengthen the evil in him. We should never use a mantra where there are people who are likely to be injured by it. p. 149"