What gets written can't be erased. It must be replaced.
A sculptor's chisel that slips and gouges a trough in the stone can't undo what it's done. The chisel's work is permanent. The tatoo artist's needle can't recall the ink from the skin: It has been absorbed as forever-dyed flesh. When humanity's faithless hoaring gouged, ruined and seared the heart, it could not be re-written:
"Judah's sin is engraved with an iron tool, inscribed with a flint point, on the tablets of their hearts ..." (Jeremiah 17:1).
The problem is, most Christians are still living here. They have been taught to sit down in that chapter, especially the verse that follows only 8 verses later: "The heart is deceitful above all things..." (Jer. 17:9)
But remember, what gets written on the heart can't be erased: It must be replaced. More specifically, you don't keep painting on a dirtied canvass: You replace the canvass first, then continue painting. You replace the heart first, then continue writing its story there. As followers of Jesus, reborn supernaturally, we've got to make the transition to a later passage in Jeremiah, leaving Jeremiah 17:9 behind:
"I will make a New Covenant with the house of Israel and with the house of Judah... I will put my law in their minds and write it on their hearts." (Jeremiah 31:31, 33). Even before God declares a new way of relating (new covenant), he expresses his intent: "I will give them a heart to know me ... for they will return to me with all their heart." (Jer. 24:7)
How can you return to God with all your heart when the heart is deceitful above all things -- Gouged, ruined? Or, how can you return to him with all your heart when you believe your heart is still deceitful above all things? You cannot. It is a crippling assumption most Christians still hold because they have been taught that they still live in Jeremiah 17:9.
What gets written cannot be erased. It must be replaced. God replaces the ruined heart with a good, pure and noble heart. (Ezekiel 36:26) There is new writing on this heart. A new way. You do know God, you do want him. Within the heart he gave you, Christian, there are supernatural kindnesses, passions, and courages you never thought possible.
He has done his best writing in you.