Transformation of the mind takes some time as you wait for the old sexual pollution to be washed away. It’s much like living near a creek that becomes polluted when a sewer main breaks upstream. After repair crews replace the cracked sewage pipe, it will still take some time for the water down-stream to clear.
In transforming your mind, you’ll be taking an active, conscious role in capturing rogue thoughts, but in the long run, the mind will wash itself and will begin to work naturally for you and your purity by capturing such thoughts. With the eyes bouncing away from sexual images and the mind policing itself, your defenses will grow incredibly strong.
Do not conform any longer to the pattern of this world, but be transformed by the renewing of your mind. Then you will be able to test and approve what God’s will is–His good, pleasing and perfect will. (ROMANS 12:2)