Therefore, my son, refine the youthful impulses of your flesh, and through the virtues we have described strengthen your immortal soul and renew your intellect with the help of the Spirit. For the flesh of youth, gorged with food and wine, is like a pig ready for slaughter. The flames of sensual pleasure kill the soul, while the intellect is made a prisoner by the fierce heat of evil desire and cannot then resist such pleasure. For when the blood is heated the spirit is cooled.

St. Mark the Ascetic, Letter to Nicolas the Solitary