It’s quite true that man’s mind has shared in the devastating effects of the Fall The “total depravity” of man means that every constituent part of his humanness has been to some degree corrupted, including his mind, which Scripture describes as “darkened.” Indeed, the more men suppress the truth of God which they know, the more “futile,” even “senseless,” they become in their thinking. They may claim to be wise, but they are fools. Their mind is “the mind of the flesh,” the mentality of a fallen creature, and it is basically hostile to God and his law. (Ephesians 4:18; Romans 1:18-23; 8:5-8)
All this is true, but the fact that man’s mind is fallen is no excuse for a retreat from thought into emotion, for the emotional side of man’s nature is equally fallen.
Then, in spite of the fallenness of man’s mind, commands to think, to use his mind, are still addressed to him as a human being (Isaiah 1:18). In other words, why don’t you use your brains? Why don’t you apply to the spiritual and moral realm the common sense which you sue in the physical? (Matthew 16:1-4; Luke 12:54-57)
-John Stott, Your Mind Matters, 16-17.