For the avoidance of errors, have someone to advise you—a spiritual father or confessor, a brother of like mind; and make known to him all that happens to you in the work of prayer.
For yourself, act always in great humility and with the utmost simplicity, not ascribing any success to yourself. Know that true success is achieved within, unconsciously, and happens as imperceptibly as the growth of the human body.
Therefore when you hear an inner voice saying ‘Ah ! Here it is ! ‘ you should realize that this is the voice of the enemy, showing you a mirage rather than the reality. This is the beginning of self-deception. Stifle this voice immediately, otherwise it will resound in you like a trumpet, inflating your self-esteem.
THEOPHAN THE RECLUSE, The Art of Prayer, p. 116