Question: "What does it mean that the heart is desperately wicked in Jeremiah 17:9?"
Answer: Jeremiah 17:9 says, “The heart is deceitful above all things, and desperately wicked: who can know it?” (KJV). The immediate context of the verse speaks of Judah’s sinfulness in spite of all the blessings of God. Jeremiah 17:1 says, “Judah’s sin is engraved with an iron tool, inscribed with a flint point, on the tablets of their hearts and on the horns of their altars.” Saying that their sin is inscribed on the tablets of their hearts is similar to saying that they are “desperately wicked” in verse 9.
The phrase desperately wicked is from the KJV. Some of the modern translations use other wording such as “beyond cure” (NIV) and “desperately sick” (NASB and ESV). The Hebrew word translated “desperately wicked” has the idea of a terminal, incurable illness.
While the immediate context speaks of the nation of Judah, that nation illustrates the human condition that is true everywhere and for everyone. This is a concept that theologians have called “total depravity.”
Romans 1—3 speaks of the total depravity of mankind. The following verses serve to illustrate the point:
Romans 1:29–32: “They have become filled with every kind of wickedness, evil, greed and depravity. They are full of envy, murder, strife, deceit and malice. They are gossips, slanderers, God-haters, insolent, arrogant and boastful; they invent ways of doing evil; they disobey their parents; they have no understanding, no fidelity, no love, no mercy. Although they know God’s righteous decree that those who do such things deserve death, they not only continue to do these very things but also approve of those who practice them.”
Romans 3:9–18: “What shall we conclude then? Do we have any advantage? Not at all! For we have already made the charge that Jews and Gentiles alike are all under the power of sin. As it is written: ‘There is no one righteous, not even one; there is no one who understands; there is no one who seeks God. All have turned away, they have together become worthless; there is no one who does good, not even one.’ ‘Their throats are open graves; their tongues practice deceit.’ ‘The poison of vipers is on their lips.’ ‘Their mouths are full of cursing and bitterness.’ ‘Their feet are swift to shed blood; ruin and misery mark their ways, and the way of peace they do not know.’ ‘There is no fear of God before their eyes.’”
Not every person will commit all the sins listed above. Total depravity does not mean that every person is as bad as he possibly can be, but that every person is completely consumed by sin and there is no hope of his turning it around and “getting better’ on his own. We are “desperately wicked.” Romans 8:8 says, “Those who are in the flesh cannot please God.” In the flesh in context refers to the natural person who has not been regenerated by the Spirit of God. The “illness” is terminal and incurable—so much so that Paul describes the unregenerate as “dead in sins” (Ephesians 2:1; Colossians 2:13).
The only hope for the sinful human heart is to be supernaturally changed. Jeremiah 31:33 gives the solution. Where sin was once inscribed on the hearts of His people, God provides a new inscription: “For this is the covenant that I will make with the house of Israel after those days, declares the Lord: I will put my law within them, and I will write it on their hearts. And I will be their God, and they shall be my people.”
Jesus came to inaugurate a New Covenant so that sins could be forgiven and sinners could be born again (John 3:5). As “desperately wicked” people, we cannot reform our hearts by our own effort. The only solution is for God to make our hearts new, washed clean from sin and fundamentally reoriented toward pleasing Him.