Other than the Gospel, there is no greater message for me to carry to those who desire to make changes in their lives than the message of heart change for life change.
What I teach those in our training classes is that the more comfortable the counselor becomes the greater the temptation to use your own wisdom in “ministering” to the counselee.  I want to remind you that we cannot do this and expect to counsel biblically because we have no wisdom of our own, at least little which is worth having.
Our counsel and our wisdom must come from the Word of God for it is the authority for the Christian; it is what sets us apart from our secular counterparts. The Word reminds us of our low position and His lofty one; as we study and apply it to our own hearts and lives we experience changes that enable us to give hope of change to others.
When helping a person in the process of change, the most critical aspect of change is showing a person the importance the heart plays in life and in behavior.  If we are to impart any wisdom to our counselees it has to begin with the understanding that the heart of man is wicked beyond all understanding.  
We strongly believe that the only way real true change will take place in a person’s life is through the change of heart. We cannot offer a person any means of change other than that which takes place in the heart and mind.
Attempts at behavior modification may be effective either in the short or long term for some people, but unless the person comes to believe in their heart that change needs to take place the change will not stick.
The Bible has much to say about the heart. Over 500 times the Bible speaks of the heart, so it must be important! Interestingly enough, it does not use today’s fluffy emotional terminology to describe the heart.  In many cases the Bible uses thought provoking imagery to lead us to understanding and right conclusions about the heart.
Look at this verse:
As in water face reflects face, so a man’s heart reveals the man. Proverbs 27:19 (NKJV)
What does this mean? As water acts like a mirror and shows what we look like on the outside, the heart reflects and reveals what we are like on the inside.  This is news to many people and scary news at that!
Jesus said, “The good man brings good things out of the good stored up in his heart, and the evil man brings evil things out of the evil stored up in his heart. For out of the overflow of his heart his mouth speaks.” Luke 6:45 (NIV)

“But the things that come out of the mouth come from the heart, and these make a man ‘unclean.’ For out of the heart come evil thoughts, murder, adultery, sexual immorality, theft, false testimony, slander.”  Matthew 15:18-19 (NIV) 
For my purposes here today, I am going to look at the evil that comes from the evil stored up in his heart, how the mouth is the revealer of the heart, and how we can gain much insight from these truths.
Whether you realize it or not, listening to what a person says will give you a huge clue as to what is going on in their heart.  Because heart change is centered on conviction by the Scriptures, we must look to God’s view of the heart found in Jeremiah 17:9:
The heart is deceitful above all things, and desperately wicked; who can know it? Jeremiah 17:9 (NKJV)

Because of this great propensity toward sin we are able to deceive even ourselves as to how wicked we are. Have you ever stopped to think about what that really means? We like to comfort ourselves with self-deception that says we aren’t really all that bad.  We don’t think of ourselves as a Charles Manson, a Jeffrey Dahmer, or an Aileen Warnol. None of us are mass murderers or prostitutes; we have not done anything on par with those kinds of people.
But we have all, every one of us- been angry enough to want to kill someone. We have committed murder in our hearts many times over (Matt 5:21) in our anger and rage.
You may not put yourself in the class of Hugh Hefner, or Larry Flint, but anyone who has ever lusted after someone has been equally as immoral in their heart as they are in their actions.  Actions, by the way, that reveal what fills their heart.
If this surprises you, it shouldn’t.  A person with a proper theology of man will understand that the heart is evil and wicked. (The problem is that so few have good theological teaching anymore!) The deceptiveness of the heart is what helps us to deny that we are “that bad” and helps us to lie to ourselves about how good we are.  It helps us to think of ourselves more highly than we ought to think of ourselves. It encourages us to be prideful and self-serving and self-indulgent.
Is it any wonder that we struggle with heart change?
To add to all this, the deceitful heart is bent on satisfying “me,” having my own way, living life for my pleasures, with “me” at the center of my universe.  If we are honest with ourselves, we may see that we have some of the sin habits found in the following passage:
But the things that proceed out of the mouth come from the heart, and those defile the man. For out of the heart come evil thoughts, murders, adulteries, fornications, thefts, false witness, slanders. These are the things that defile the man… Matthew 15:18-20a, NASB

And, if we are honest with ourselves, we will begin to realize we tend to minimize our sinful heart attitudes. This leads to some of them becoming respectable sins as Jerry Bridges says. Angry outbursts and gossip and lies become non-issues in the heart, so they become non-issues in the life. 
So as we read Jesus’ words, we see our biggest problem lies within our own heart. Even after salvation, the basic nature of the human heart is still self-willed and blind to its own corruption and propensity toward sin.  We describe ourselves and others as having “a good heart” but honestly nothing could be further from the truth! 
The heart of man is unbelievably wicked and sinful; to such a great degree that we are unable to determine how bad it really is because it lies to us! It is like the color black trying to discern how black it is. The heart is where greed and envy and love of self are located. 
Our heart’s are set upon pleasing self above all.