“To receive and behold in the heart the light of Christ, one must, as far as possible, divert one’s attention away from visible objects. Having purified the soul beforehand by repentance and good deeds, and with faith in the Crucified, having closed the bodily eyes, immerse the mind within the heart, in which place cry out with the invocation of the name of our Lord Jesus Christ; and then, to the measure of one’s zeal and warmth of spirit toward the Beloved, a man finds in the invoked name a delight which awakens the desire to seek higher illumination.

When through such a practice the mind enters into the heart, the light of Christ shines, illuminating the chamber of the soul by its Divine radiance, as the Prophet Malachi says: ‘But unto you that fear My name, the Sun of justice shall arise (Mal. 4:2)’.
The light is likewise life, according to the word of the Gospel: ‘In Him was life, and the life was the light of men (St. John 1:4)’.

When a man beholds the eternal light interiorly, his mind is pure and has in it no sensory representations, but, being totally immersed in contemplation of uncreated goodness, he forgets everything sensory and wishes not even to see himself; he desires rather to hide himself in the heart of the earth, if only he be not deprived of this true good – God.”
Text from "Spiritual Instructions of St. Serafim of Sarov", printed by Saint Herman of Alaska brotherhood, Platina, California 1978