Today I want to focus a bit on the application of the Roots-and-Fruits Principle
Jesus said, “A tree is identified by its fruit. Make a tree good, and its fruit will be good. Make a tree bad, and its fruit will be bad” (Matthew 12:33, NLT).
The quality of the fruit of any tree depends on the root system of that tree. When the roots are growing in deep, rich soil full of nutrients, the tree will be strong and healthy. The fruit of that tree will be juicy, sweet, and resistant to bugs and parasites.
The tree rooted in poor quality soil will have little nutrition to carry up through the trunk to the branches and leaves. The tree will be weak and susceptible to disease. The quality of its fruit will be poor. You could return year after year and pluck the poor fruit from the tree, but that would not change the health of the tree. The tree would remain sickly and vulnerable, bearing bad fruit. The only way to cause a tree to produce good fruit is to attend to the roots.
To make application to your life, if you address only your feelings (fruit), you will revisit the sinful fruit you seek to get rid of in a short time. There is a problem to deal with deeper down in your tree of life. Something has caused your fruit to be bad. You must address the root system. Deal with your sinful behaviors by attacking the real causes (roots) in a biblical manner.
You have to deal with the heart of your problem in order to overcome it. In the case of humanity, the root system is equal to the heart.
No matter what sin you struggle with, you have to realize that you sin because you have focused your heart on your wants, your perceived needs, your personal rights, your beliefs and desires. This results in a self-centered, idolatrous heart, which is revealed by your thoughts, words, and actions.
If you are depressed, chances are you came to believe you needed certain things or people to “make you happy.” Yet even though you may have gotten those things, you find you are still unhappy.
If you lie, you believe you will not get caught, you believe you are too smart to get caught, and you believe you are entitled to have/do/be whatever you are lying about. You are also ruled by fear.
If you are sexually immoral in any manner, you think no one is aware of your sin. You believe you won't get caught and that it won't hurt you. You believe you are entitled to feel good and be happy. You desire the feelings your sexual immorality brings you.
Self-focused motivations spurred on by the desires of the sinful heart have produced the kind of fruit you would expect—depression and discouragement.
What’s the cure for sin? It may surprise you that biblical counseling does not focus on the fruit of a specific sin most of the time. It is not profitable to simply pull the bad fruit off the tree, because new bad fruit will soon grow in its place. The sin you are committing is the result of the problem, not the problem itself.
The way to deal with all sin biblically is to determine the source of the feelings—your beliefs, desires, and thoughts. The Bible says that the source to examine is your heart.
Your heart focus must change from being "all about me" to glorifying God.