Awhile back, my son and I had a conversation about the term “tablet of your heart”. A tablet is made of stone, just look at the tablets the Ten Commandments were written on. So to write something on the tablet of the heart it is going to do something permanent to the heart. Why? Because in order to write something on a stone part of the stone will be removed. It takes a lot of effort to engrave something into to stone. There are going to be pieces that have to be removed, It is going to be a permanent change to that stone tablet.
In Jeremiah 17, we see that Judah has thier sin engrave on their tablet of the heart. I would not want to be known forever by something bad that I had done. Which lead to their destruction.
In Proverbs chapters 3,6,and 7, we see three things that are to be engraved into out hearts.
Mercy — checed: kindness; by implication (towards God) piety; rarely (by opposition) reproof, or (subjectively) beauty:—favour, good deed(-liness, -ness), kindly, (loving-) kindness, merciful (kindness)
Truth — ’emeth: stability; (figuratively) certainty, truth, trustworthiness:—assured(-ly), establishment, faithful, right, sure, true (-ly, -th), verity
Commandments — mitsvah: a command, whether human or divine (collectively, the Law):—(which was) commanded(-ment), law, ordinance, precept
For when we do what God says for us to do, we will have a long life and peace.