Human behavior is a mystery. Isaac Newton said, “I can calculate the motion of heavenly bodies, but not the madness of people.”
The movement of the stars and planets can be measured with precision. The behavior of people is not so easily determined. In college, I minored in psychology because I wanted to understand why people did the things they did. It wasn’t just other people that had me wondering. I didn’t even understand my own behavior. Too often, I regretted something I did or said, and questioned why I did or said it. However, my psychology courses didn’t fully answer those questions for me. It was only after I began to study the Bible that I received insight into human nature.
Our hearts are the problem.
The human heart is the most deceitful of all things, and desperately wicked. Who really knows how bad it is? Jeremiah 17:9
Jesus said, “Whatever is in your heart determines what you say” (Matthew 12:34). On another occasion, in Mark 7:21, He said “For from within, out of a person’s heart, come evil thoughts, sexual immorality, theft, murder, adultery, greed, wickedness, deceit, lustful desires, envy, slander, pride, and foolishness.”
And the Proverbs writer reminds us, in Proverbs 4:23, Guard your heart above all else, for it determines the course of your life.
We are all born with a sin nature. Mankind inherited it from Adam and Eve. Before people know the Lord, they are controlled by the sinful nature. When we come to God through faith in Jesus, He gives us a new nature, and transformation begins. We are saved from the penalty of sin the moment we acknowledge it, repent of it, and accept Jesus death on the cross for our sake. Therefore, there is now no condemnation for those who are in Christ Jesus (Romans 8:1). But while we are still in these human bodies, the old nature and the new nature are in a struggle. The transformation within us is called sanctification. It is a life-long process.
Human behavior is a mystery. In Romans 7 the apostle Paul describes his own struggle with obedience to God’s law. The problem is not with the law. The law is spiritual and good. It is the law that makes us aware of the sin in our lives. Paul reports about himself, “I want to do what is good, but I don’t. I don’t want to do what is wrong, but I do it anyway” (Romans 7:19). He continues, “I love God’s law with all my heart. But there is another power within me that is at war with my mind. This power makes me a slave to the sin that is still within me” (Romans 7:22-23).
It’s easy to identify with Paul wanting to do right, but not doing it, and vice-versa.
A story is told about G. K. Chesterton who was asked, “What is wrong with the world?” He answered simply,” I am.” That is true for each of us. God works within us to make us more like Christ. The more we yield to the Holy Spirit working in our lives, the less our old nature controls us.
Human behavior isn’t such a mystery after all. A frequent prayer of mine is, “Lord, make my heart right.” I am thankful the Lord is so patient and gracious as He works in me.
Create in me a clean heart, O God, and renew a right spirit within me. Psalm 51:10 ESV
How does it encourage you to know we don’t have to be controlled by our old nature as we yield to the Holy Spirit’s work in us? Please leave a comment below.
Blessings,
Phyllis
© 2026 Phyllis L. Farringer
Image by Volodymyr from Pixabay
This explains a lot. Have always been confused about human behavior, including my own particularly.
Praise God that as He works in us, changing us from the inside, He gives us the desire and power to do what pleases Him. Apart from Him, we would be completely lost. Thanks for reading, George.
G.K. Chesterton’s quote nailed it!
and so did you!
Thank you.
G.K. Chesterton usually nails it. Thank you, Debby.
Thanks for the post, Phyllis. I always pray for God to give me a clean heart and a clear mind – AND to direct my thinking so I serve Him and not harm others with my actions or words.
That’s a good prayer. Thank you, Joni.