In seminary today we were studying Mark 7:1-15 where the Pharisees came and criticized Jesus' disciples for eating with unwashed hands. Jesus replied to them, "There is nothing from without a man, that entering into him can defile him: but the things which come out of him, those are they that defile the man." (verse 15).
The lesson included a quote by Elder Dallin H. Oaks: ""The body has defenses to rid itself of unwholesome food. With a few fatal exceptions bad food will only make you sick but do no permanent harm. In contrast, a person who feasts upon filthy stories or pornographic or erotic pictures and literature records them in this marvelous retrieval system we call a brain. The brain won't vomit back filth. Once recorded, it will always remain subject to recall, flashing its perverted images across your mind and drawing you away from the wholesome things in life" (Things Theyre Saying, New Era, Feb. 1974, 18).
It's a sobering thought to realize that our brain is a permanent recording device. It does not have the power to purge itself of memories. We can, however, purge ourselves spirituallly. Many say that faith in Jesus Christ is sufficient for salvation, and that we are not in need of repentance. But I know first hand the blessing that true repentance can bring to a person's soul. The ability to purge ourselves spiritually of the things that we have done that are wrong helps us to heal. Repentance requires action on our part. But through the grace of our Savior, if we do all that we can to rid our lives of that which "defileth" us, we can be forgiven. "Come now, and let us reason together, saith the Lord: though your sins be as scarlet, they shall be as white as snow; though they be red like crimson, they shall be as wool". Isaiah 1:18