St. Porphyrios on prayer of the heart
Prayer of the heart is impossible without a spiritual guide. There is a danger of the soul being deluded. Care is needed. Your spiritual guide will teach you how to get into the right order for prayer, because if you don’t get into the right order, there’s a danger of your seeing the luciferic light, of living in delusion and being plunged into darkness, and then one becomes aggressive and changes character and so on. This is the splitting of the personality. Do you see how delusion is created? If, however, you progress in prayer with the counsels of a spiritual father, you will see the true light.
The spiritual guide must be experienced in prayer of the heart. If he prays mechanically and has not experienced prayer with the grace of God, he is unable to tell someone else how to pray. Certainly, he will be able to say what he has read in books and what the Fathers say. Whole books have been written which talk about prayer. And so many people read them and none knows how to pray.
Wounded by Love