“Now this I affirm and testify in the Lord, that you must no longer live as the gentiles do, in the futility of their minds; they are darkened in their understanding, alienated from the life of God because of the ignorance that is in them, due to their hardness of heart; they have become callous and have given themselves up to licentiousness, greedy to practice every kind of uncleanness. You did not so learn Christ! Assuming that you have heard about him and were taught in him, as the truth is in Jesus.”
There is nothing in your life more important than the way you think. In this section, Paul contrasts the way of life of unbelievers (he uses “gentiles” to refer to non-believers) versus the way of life of believers. The central message is that the way of life of both non-believers and believers is driven by how they think.
The mind plays a central role in human life. The importance of thinking is reflected in how Paul describes the life of non-Christians: They live in the “futility of their minds; darkened in their understanding; alienated from the life of God because of their ignorance; hardness of heart.”
These phrases all describe the activity of the mind. A distorted mind. A mind that has been deceived. The book of Proverbs describes this kind of self-centered mindset as the thinking of a fool.
The reason why scripture places such a strong emphasis on thinking is because the way you think determines the way you live. How you think drives the decisions you make and the actions you take. Effective thinking produces productive action, but ineffective thinking produces unproductive action. Right thinking produces right action, but wrong thinking produces wrong action.
This is true every time, everywhere, for everyone. Where your mind goes, you go.
Here is another way to think about it: The quality of your inner work determines the quality of your outer work. How you manage yourself on the inside will determine how you behave on the outside. If you want to change any area of your life, you must first change your thinking.
“For as a man thinks in his heart, so is he.” (Proverbs 23.7)