Futile Thinking
Eph 4:17 So I tell you this, and insist on it in the Lord, that you must no longer live as the Gentiles do, in the futility of their thinking.
The way you think affects how you live. Your world view affects your decisions. The word for "futile" indicates that which is vain, devoid of truth and appropriateness, or perverse and depraved. Paul speaks such a state saying, "For although they knew God, they neither glorified him as God nor gave thanks to him, but their thinking became futile and their foolish hearts were darkened. Although they claimed to be wise, they became fools." Rom 1:21,22 A depraved mind is an effect of rejecting the knowledge of God. For "since they did not think it worthwhile to retain the knowledge of God, he gave them over to a depraved mind, to do what ought not to be done." Rom 1:28
So consider in what ways your lifestyle reflects a vain or depraved way of thinking.