In basic computer science, we were told that everything the computer does is because it has been programmed to do so. The  acrostic "GIGO"( garbage in garbage out)  was coined to buttress that truth. The computer only gives what has been programmed into it.

Our mind works like the computer. We are the programmer. It gives back to us what we put into it. If you feed your mind with lewd and sexually explicit content, it will produce the fruit of immorality and sexual struggles.

Any sexual struggle either with pornography, masturbation, incest, homosexual feelings, adultery&fornication are all products of what is in the mind. That is why the writer of Proverbs says, "Keep thy heart with all diligence; For out of it are the issues of life" (Prov 4:23 KJV).

If your mind has been programmed for sexually immorality, the good news is that it can be reprogrammed with the word of God. Your mind can be cleansed with scriptures and washed clean such that sexual sin will lose its grip over your life.

Psalm 119:9 says,  "Wherewithal shall a young man cleanse his way? by taking heed thereto according to thy word".

The word of God is the cleansing agent of the mind. It is powerful to renew and reconfigure your mind for sexual purity. If you are far from the word of God, you won't be far from a mind pollutant. That is certain. You cannot treat God's word casually and be sexually pure.

Romans 12:2 says, "And be not conformed to this world: but be ye transformed by the renewing of your mind, that ye may prove what is that good, and acceptable, and perfect, will of God".

Mind renewal requires that you choose to think and act line with the word of God as you study it.  Merely studying the bible doesn't renew your mind. Some professors of theology are not born again neither are they pure yet they know the bible from cover to cover.

The word of God becomes fruitful in your life as a sanitizing agent the moment you begin to think and act on it. That is how renewal takes place.