from Ligonier Ministries:
Enslavement to sin characterizes all those who have not yet been transformed by God’s saving grace, and only the Son of God, by the Holy Spirit, can set people free to do what is pleasing to the Lord (see John 8:36). This complete enslavement to sin is what we are really talking about when we speak of total depravity. The consequence of Adam’s fall is not merely that it has become more difficult to do what is truly good or that we have been weakened while still retaining some ability to choose to please God. No, the fall has rendered us unable to respond to our Creator in trust, love, and obedience.
It is important for us to be clear on what we mean when we speak of sinful humanity’s inability to choose the good. We do not mean that sinners cannot make choices. Plainly, we choose from many different options every day. We select one course of action over another. Also, we do not mean that sinners are incapable intellectually of discerning good and evil. Our moral sense has been impaired by the fall, but even the most hardened sinner still has God’s law on his conscience and can recognize the difference between good and evil on at least some level (Rom. 2).
When it comes to total depravity, the inability of which we speak is first and foremost moral inability. In our fallenness, though we have a will and can discern the good, we lack the ability to choose rightly, to exercise our wills in the proper direction of absolute dependence on God and submission to His will. To put it another way, we are dead with respect to the things of God, to that which He finds pleasing. That is what Paul says in today’s passage. Before our Creator makes us alive spiritually, we are dead in our trespasses and sin, and we cannot help but serve the world, the flesh, and the devil. Dead bodies are incapable of doing anything but remaining in the state of death. If they are to come alive again, they must be acted upon by an outside being, even God Himself at the resurrection. Spiritually dead people cannot do anything but remain in the state of spiritual death. They require an outside being—the sovereign Lord—to restore them to spiritual life. This is what God does for His people in making them spiritually alive. We see the greatness of God’s grace and power in that He intervenes and changes us before we are even able to ask Him to do so, granting us the faith by which we are saved (Eph. 2:1–10).
Coram Deo
The doctrine of total depravity and what it entails—total moral inability—magnify the grace and power of God. God is so gracious that He saves people who in their natural state are unwilling to come to Him, and He is so powerful that He never fails to redeem those whom He wants to redeem. Knowing the depth of our sin should move us to worship our Lord fervently for His goodness and grace.
from atpollard:
“Total Depravity” means that every part of man (mind, body and spirit) were impacted by the fall and are drawn to sin. “Total Inability” means that man cannot overcome his sinful nature without outside aid (from God). Thus “Total Depravity” = “Total Inability” from the standpoint of the impact of sin on man’s salvation.
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