“The tradition of our Fathers and the authority of Scripture teaches us that there are three kinds of renouncements which each of us must work to carry out with all his strength. The first is to reject all the pleasures and all the riches of this world. This second is to renounce ourselves, our vices, our wicked habits, and all the unruly affections of the spirit and of the flesh; and the third is to withdraw our heart from all things present and visible and apply it only to the eternal and invisible. God teaches us to make these three renounements all at once by what He said to Abraham first of all. “Go out!” he told him, “from your country, from your kindred, from the house of your father; that is, leave the goods of this world and all the riches of the earth. Go out from your ordinary life and from the wicked and vicious inclinations which, attaching themselves to us by our birth and the corruption of flesh and blood, are as it were naturalized and become one thing with ourselves. Go out from the house of your father, that is, lose the memory of all the things of this world and of everything that presents itself to your eyes…”
We shall then arrive at this third renouncement when our spirit, no longer weighed down by the contagion of this animal and earthly body, but purified from the affections of the earth, is raised to heaven by continual meditation on divine things, and is so taken up with the contemplation of the eternal truth that it forgets that it is still enclosed in fragile flesh and, ravished in God, it will find itself so absorbed in His presence that it has no longer ears to hear or eyes to see and it cannot even be struck by the greatest and most perceptible objects.”
(St. John Cassian, in Louis Bouyer’s The Spirituality of the New Testament and the Fathers, p. 327)