The ways of access of the sin
27 “You have heard that it was said, ‘You shall not commit adultery.’[a] 28 But I tell you that anyone who looks at a woman lustfully has already committed adultery with her in his heart. 29 If your right eye causes you to stumble, gouge it out and throw it away. It is better for you to lose one part of your body than for your whole body to be thrown into hell. 30 And if your right hand causes you to stumble, cut it off and throw it away. It is better for you to lose one part of your body than for your whole body to go into hell.
31 “It has been said, ‘Anyone who divorces his wife must give her a certificate of divorce.’[b] 32 But I tell you that anyone who divorces his wife, except for sexual immorality, makes her the victim of adultery, and anyone who marries a divorced woman commits adultery.
The debauchery comitted with the soul
Saint Basil the Great, Homilies and speeches, Homily XXII to the young, VII, in Church Fathers and Writers (2009), vol. 1, p. 331
`I will not ignore the deed of Alexander (the Great) who when taking as slaves the daughters of Darius famous for their beauty did not want to see them at all as he considered shamefully for the one who had defeated men to be defeated by women. Alexander`s deed resembles this evangelic commandment:
`who looks at a woman lustfully even if he had not committed in deed the adultery is not forgiven of the sin as he has already committed adultery with her in his heart.` (Matthew 5, 28).”
Saint Makarios the Egyptianul, The fifty spiritual homilies, Homily XXVI, 13, in Church Fathers and Writers (1992), vol. 34, pp. 208-209
`If you guard your body only outwardly of debauchery and you make debauchery in your thoughts you are a debaucher before God and it is of no use for you if you have a virgin body. As when a young man by fooling and corrupting a young girl this one is despised by her bridegroom because she debauched the immaterial soul getting in touch with the snake hidden inside itself, with the cunning spirit, commits debauchery before God.
As it was written: `anyone who looks at a woman lustfully has already committed adultery with her in his heart. ` (Matthew 5, 28).
That is why we say that there is a debauchery committed with the body and a debauchery committed in the soul when this one is in communion with Satan. The same soul may be partaker and brother of the demons but also of God and the angels but if the soul debauches with the devil it becomes worthless before the heavenly Bridegroom.`
Saint Gregory of Nyssa, Homilies at Ecclesiast, Homily V, in Church Fathers and Writers (1992), vol. 30, p. 236
`(…) The soul of such a fool dedicates only to the pleasure of the flesh and he turns himself into a pile of flesh and while he looks at them he doesn`t see anything in fact because when you focus your look only on the pleasures of the senses then you don`t reach anywhere else than in darkness.`