Melting the Stone

The Chidushei Harim zy”a sees this verse as a hint that even people whose hearts are as hard as stone can be returned to the proper path through words of Torah. This is as Chazal say (Sukkah 52B): “If it is made of stone, it will melt.”

This means that the yeitzer hara can be overcome through the power of Torah. The pasuk is saying that even if Torah is written on stones, meaning in a heart of stone, it can have the effect of annulling the yeitzer hara completely.