They told of Abba Macarius the Great that one day when he was walking around in the desert, he found the skull of a dead person thrown on the ground. [The elder] prodded it with his palm staff and said, “You, who are you? Answer me!” and the skull spoke to him, saying, “I was the high priest of the pagans who inhabited this place, and you are the spirit-bearing Abba Macarius. Whenever you feel compassion for those in chastisement, they are a little relieved.” Abba Macarius said to him, “Relieved in what way?” The skull said to him, “There is as much fire beneath our feet and heads as the sky is distant form the earth. Stationed in the midst of the fire, it is not possible to see each other face to face, being glued back to back. When you pray for us, one has a partial glimpse of the face of the other.” Weeping, the elder said, “Sad was the day in which a person was born if this is the relief of the chastisement!” The elder said to him again, “Is there another punishment worse than this one?” The skull said to him, “There is a great punishment beneath us.” [The elder] said to him, “And who is in it?” The skull said to him, “We who did not see God are at least a little pitied; but they who saw God but denied him and did not do his will, they are the ones beneath us.” After that the elder took the skull, buried it in the ground, and went his way.
(THE BOOK OF THE ELDERS, 3.19)