Spiritual Formation and Overcoming Pornography by Dallas Willard
"The use of pornography is rooted in the fundamental role of desire in human life. Desire, on the biblical understanding, is not in itself bad, but it is dangerous because it has the tendency to take over one’s life. Desire must be subordinated to what is good, and it is the role of the will to see to it that it is subordinated to what is good. But the will can do this only if it understands what is good and is strongly oriented toward it. This is definitely not the case with those unaligned with God. In them the will falls captive to desire: they live to do what they want. Their condition is repeatedly addressed in the scriptures.
The general condition of fallen humanity is carefully laid out by Paul in Ephesians 4:17-19 and Romans 7:15-23. The will is, in the fallen personality, enslaved by desire, and so "I am doing the very thing I hate." (vs. 15) This is a precise picture of the person in some degree of bondage to pornography.
We really must pay attention to desire ("lust," "longing," επιθυμία) if we are to understand spiritual formation. The primary role of desire in human life is to impel us to action. If action were solely under the direction of thought, we would never survive infancy, and life would be an intolerable burden in which much that is good would not be realized. Lusting itself gives pleasure, because it thrusts us in a direction and makes us feel alive. We are "moved," hence we speak of "passion." Thus we get pleasure from desiring itself, and desire to desire. The gratification of desire gives us a sense of completeness and power—for a moment or so. A depressed person is typically one who has little or no desire and "doesn’t want anything."
Thus we do many things just to excite desire." (MORE)
"Grace and peace be multiplied to you in the knowledge of God and of Jesus our Lord; seeing that His divine power has granted to us everything pertaining to life and godliness, through the true knowledge of Him who called us by His own glory and excellence. For by these He has granted to us His precious and magnificent promises, so that by them you may become partakers of the divine nature, having escaped the corruption that is in the world by lust."-- 2 Peter 1:3-4