It is said that when we begin practicing the sublime Dharma, negative forces create obstacles, and their “blessing” causes our faith to diminish. Signs that the demons have entered us are that we find fault in the spiritual friend, our teacher; we see defects in Dharma practitioners in general; we keep the company of ordinary people; we have less diligence in the practice; we indulge in pleasure heedlessly, without any moral principles; and our devotion and respect for the Three Jewels fades.
How can these be prevented? Reflecting on the excellent qualities of the teacher, the Three Jewels, and your spiritual companions, develop pure perception and respect for all who practice the Dharma. Tell yourself that seeing bad in other people is a sign that you yourself are impure: it is as if you were jaundiced and perceived conch shells as yellow. Remind yourself of the defects of the pleasures of the senses, and avoid befriending ordinary people. Recognize that a decrease in faith is a demon.