Question: What is the source of evil thoughts that disturb those who do not wish to entertain them?
Answer [by 'Abdu'l-Baha]: “They come from other minds; they are reflected. One should not become a mirror for them - to reflect them; neither should one try to control them, for this is impossible; it only aggravates the difficulty, causing more to appear.
One should constantly turn the mirror of his heart squarely toward God so that the Light of the Sun of Truth may be reflected there.
This is the only cure for attacks of evil thoughts. The face of the mirror should be turned toward God, and the back of the mirror toward the evil thoughts.”
- "Abdu'l-Baha (Utterances of 'Abdu'l-Baha, quoted by Helen Goodall and Ella Goodall Cooper in ‘Daily Lessons Received at Akka January 1908')