This study of Romans 1 comes from Jon Cardwell at Justification by Grace. This post focuses on the reprobate mind...
The New American Standard Bible translates the verse in this way: “And just as they did not see fit to acknowledge God any longer, God gave them over to a depraved mind, to do those things which are not proper.” Fallen, sinful, unsaved, and unrepentant men didn’t care anything about God to even acknowledge Him. Interestingly, this is worse than someone who claims to be an atheist, a person who vehemently opposes the existence of God. The atheist, at the very least through their denials and opposition, acknowledge that others believe in God; which in itself is some acknowledgement of God. The people spoken of in this passage are far worse than that; they don’t even acknowledge God and care nothing for Him or about Him.
So the mind was reprobate and depraved. The fall of mankind, through Adam’s disobedience, corrupted every area of the human condition. Man did not become as bad as he could possibly be; however, man’s depravity was so complete that sin touched and tainted every area of fallen man’s being. That which allowed him to act out his sinfulness was his depraved mind. The Greek word, translated “mind” here, is also translated “understanding” and refers to the seat of the will and the home of one’s intellect.
When a man’s mind goes, then his will corresponds wherever his mind has gone; and if God has given the heathen over to reprobate minds, those sinners will act upon their depravity. This is why the reading, preaching, hearing, studying and meditating upon the Word of God is so very, very important; for it is by the Word of God that the Lord cleanses and sanctifies His church (Ephesians 5:26; John 17:17).
"Afresh, precious, precious Jesus, I resign this body to You, for doing or suffering, for living or dying. Will You accept it? Will You use me for Your glory more than heretofore, that You may have some little return for all the benefits You have done to me? Oh, do grant this request; my heart longs for it, my spirit pleads for it; and "if You will, You can." You know the hot temptation of which I am the subject. Bring Your glory out of it, and keep me from the evil, and it shall be well." - Ruth Bryan