As a counselor and a social worker, I have studied a vast number of psychological theories related to human behavior. And although some of these theories can provide a level of insight into how we behave, all of these theories are tainted because they have been developed by humans, and therefore, by their very nature are imperfect. So, to gain true insight into human behavior, one needs to look to scripture, which was revealed to humankind by a perfect and true God. A good place to start to understand who we are as humans is in the Book of Romans in the New Testament, for there God reveals two different ends of the spectrum for humankind, the nature of those who have rejected God, and the nature of those who are in Christ Jesus the Lord.
In the first chapter of Romans, God states that those who reject God are given over to “the lusts of their hearts”. (Romans 1:16-25, NASB “For the wrath of God is revealed from heaven against all ungodliness and unrighteousness of people who suppress the truth in unrighteousness, because that which is known about God is evident within them; for God made it evident to them. For since the creation of the world His invisible attributes, that is, His eternal power and divine nature, have been clearly perceived, being understood by what has been made, so that they are without excuse. For even though they knew God, they did not honor Him as God or give thanks, but they became futile in their reasonings, and their senseless hearts were darkened. Claiming to be wise, they became fools, and they exchanged the glory of the incorruptible God for an image in the form of corruptible mankind, of birds, four-footed animals, and crawling creatures. Therefore God gave them up to vile impurity in the lusts of their hearts, so that their bodies would be dishonored among them. For they exchanged the truth of God for falsehood, and worshiped and served the creature rather than the Creator, who is blessed forever”.) And ultimately, the lusts of the heart leads to despair, condemnation, and death. For a deeper understanding of the lusts of the heart and what is detestable to God, I would encourage anyone to read through the whole first chapter of Romans, for it provides insight into why the world looks like it does today.
Now, on the other side of the spectrum are those who have put their faith in Christ Jesus as their Lord and Savior, as revealed in Chapter 8 of Romans (verses 1-17). “Therefore there is now no condemnation at all for those who are in Christ Jesus. For the law of the Spirit of life in Christ Jesus has set you free from the law of sin and of death. For what the Law could not do, weak as it was through the flesh, God did: sending His own Son in the likeness of sinful flesh and as an offering for sin, He condemned sin in the flesh, so that the requirement of the Law might be fulfilled in us who do not walk according to the flesh but according to the Spirit. For those who are in accord with the flesh set their minds on the things of the flesh, but those who are in accord with the Spirit, the things of the Spirit. For the mind set on the flesh is death, but the mind set on the Spirit is life and peace, because the mind set on the flesh is hostile toward God; for it does not subject itself to the law of God, for it is not even able to do so, and those who are in the flesh cannot please God. However, you are not in the flesh but in the Spirit, if indeed the Spirit of God dwells in you. But if anyone does not have the Spirit of Christ, he does not belong to Him. If Christ is in you, though the body is dead because of sin, yet the spirit is alive because of righteousness. But if the Spirit of Him who raised Jesus from the dead dwells in you, He who raised Christ Jesus from the dead will also give life to your mortal bodies through His Spirit who dwells in you. So then, brothers and sisters, we are under obligation, not to the flesh, to live according to the flesh— for if you are living in accord with the flesh, you are going to die; but if by the Spirit you are putting to death the deeds of the body, you will live. For all who are being led by the Spirit of God, these are sons and daughters of God. For you have not received a spirit of slavery leading to fear again, but you have received a spirit of adoption as sons and daughters by which we cry out, “Abba! Father!” The Spirit Himself testifies with our spirit that we are children of God, and if children, heirs also, heirs of God and fellow heirs with Christ, if indeed we suffer with Him so that we may also be glorified with Him”.
For the Christian, putting our faith in Christ Jesus as our Lord and Savior does not automatically make us perfect human beings, because we still have our sinful nature to contend with throughout our earthly lives. However, we have hope because the Spirit of God indwells in us, and therefore we are no longer under obligation to live in captivity to the lusts of the heart. For the things of the flesh (sin) are detestable to God, and sin leads to death. But through the Spirit we can put to death the lustful deeds of the body, and live a life pleasing to God, and ultimately have eternal life through Christ. “For the wages of sin is death, but the gracious gift of God is eternal life in Christ Jesus our Lord” (Romans 6:23).