"By constant meditation upon his Guru, and ardent aspiration towards him, the pupil has so affected his own vehicles that they are constantly open towards his Master and expectant of his influence. At all times they are largely preoccupied with that idea, waiting the word of the Master and watching for something from him, so that while they are keenly and sensitively open to him they are to a considerable extent closed to lower influences. Therefore all his higher vehicles, from the astral upwards, are like a cup or funnel, open above but closed at the sides, and almost impervious to influences touching him at the lower levels."
January 1, 1970
https://en.wikiquote.org/wiki/Masters_of_Wisdom_(Theosophy)