Question: They come because they are invoked?Sri Chinmoy: Most of the time angels have to be invoked. Again, many, many times they come without being invoked — they can come unconditionally. Usually people invoke angels unconsciously. Consciously, people think of God and then God may send an angel as His emissary.
Sri Chinmoy, Sri Chinmoy answers, part 25, Agni Press, 2000