“The sin of Judah is written with a pen of iron; with a point of diamond it is engraved on the tablet of their heart, and on the horns of their altars, while their children remember their altars and their Asherim, beside every green tree and on the high hills, on the mountains in the open country” (Jeremiah 17:1–3a).
Sin being engraved on the heart isn’t so much the diagnosis as the prognosis. Here we’re not told the disease itself as of its advanced stages. Jeremiah will soon speak of humanity’s heart condition in verse 9. “The heart is deceitful above all things, and desperately sick; who can understand it?” At the beginning of the chapter though, we see what happens when the sin-sick heart pumps sin after sin after sin.
Man, born totally depraved advances toward being utterly depraved. The more the heart flows with wickedness, the darker the flow of wickedness becomes. Sin, having flowed out of the heart, is then engraved on the heart. Heart-hardening is the result of our hereditary heart disease.
But it is not the heart being likened to a tablet which speaks to this hardness. The father of Proverbs pleads, “My son, do not forget my teaching, but let your heart keep my commandments, for length of days and years of life and peace they will add to you. Let not steadfast love and faithfulness forsake you; bind them around your neck; write them on the tablet of your heart” (Proverbs 3:1–3, emphasis mine). The heart is a tablet. It is what is written on it that is indicative of hardness.
In an oral culture the important and that which was to be preserved were written. Writing something on paper indicates was significant; engraving it on stone far more. Judah’s sin is indelible, ineffaceable, ineradicable.
This is humanity’s prognosis. We are all terminally ill. And because our hearts are deceitful, we are in denial. Our only hope is that the Great Physician, in mercy, grant us new hearts in the new covenant (Jeremiah 31:31–34; 32:36–41; Ezekiel 36:24–32).