...continue the explain

In cases in which good or evil thoughts are projected at individuals, those thoughts, if they are to directly fulfil their mission, must find, in the aura of the object to whom they are sent, materials capable of responding sympathetically to their vibrations. Any combination of matter can only vibrate within certain definite limits, and if the thought-form be outside all the limits within which the aura is capable of vibrating, it cannot affect that aura at all. It consequently rebounds from it, and that with a force proportionate to the energy with which it impinged upon it. This is why it is said that a pure heart and mind are the best protectors against any inimical assaults, for such a pure heart and mind will construct an astral and a mental body of fine and subtle materials, and these bodies cannot respond to vibrations that demand coarse and dense matter. If an evil thought, projected with malefic intent, strikes such a body, it can only rebound from it, and it is flung back with all its own energy; it then flies backward along the magnetic line of least resistance, that which it has just traversed, and strikes its projector; he, having matter in his astral and mental bodies similar to that of the thought-form he generated, is thrown into respondent vibrations, and suffers the destructive effects he had intended to cause to another. Thus "curses [and blessings] come home to roost." From this arise also the very serious effects of hating or suspecting a good and highly-advanced man; the thought-forms sent against him cannot injure him, and they rebound against their projectors, shattering them mentally, morally, or physically. Several such instances are well known to members of the Theosophical Society, having come under their direct observation. So long as any of the coarser kinds of matter connected with evil and selfish thoughts remain in a person's body, he is open to attack from those who wish him evil, but when he has perfectly eliminated these by self-purification his haters cannot injure him, and he goes on calmly and peacefully amid all the darts of their malice. But it is bad for those who shoot out such darts.

Explain the Thought-forns

Thought-forms directed towards individuals produce definitely marked effects, these effects being either partially reproduced in the aura of the recipient and so increasing the total result, or repelled from it. A thought of love and of desire to protect, directed strongly towards some beloved object, creates a form which goes to the person thought of, and remains in his aura as a shielding and protecting agent; it will seek all opportunities to serve, and all opportunities to defend, not by a conscious and deliberate action, but by a blind following out of the impulse impressed upon it, and it will strengthen friendly forces that impinge on the aura and weaken unfriendly ones. Thus may we create and maintain veritable guardian angels round those we love, and many a mother's prayer for a distant child thus circles round him, though she knows not the method by which her "prayer is answered."

extract Thought-Forms
C. W. Leadbeater and Annie Besant