“The human heart is the most deceitful of all things, and desperately wicked. Who really knows how bad it is?” (Jer 17.9 NLT)
The Hebrew word that is translated “heart” here is לֵב which can also be translated as “mind”. So, put another way, the mind is the most deceitful of all things, desperately wicked; who can understand it indeed.
Research has found that each person possesses two minds: the conscious mind and the unconscious mind. While we would like to believe that most of our actions are directed by our conscious mind, the truth is that they are directed by our unconscious mind. This is why we lie even though we believe that telling lies is wrong; this is why we allow ourselves entertain having an extra-marital affair and later justify it fervently, albeit irrationally, when we finally act out our fantasies.
You have heard it said that “the longest distance is between the mind and the heart”. (Without knowing it, they are making reference to the conscious (former) and the unconscious (latter) minds.) This is because education of the mind hardly automatically translates into conviction and reformation of the heart (or unconscious mind). Here is where Christian Education has failed. After all the teaching, many Christians still lead unchanged lives because their unconscious minds have largely remained untouched. Their conduct betray their confessions. In the words of James, they are hearers of the Word but not doers of it (James 1:22). From James we learned that they are suffering from Self-deception.