The Stone at the Well and the Heart of Stone

When the shepherds assembled, they also had the power to remove the stone from the mouth of the well. Only that it says afterwards, they returned the stone to its place... whereas by Yaakov who was a Tzaddik it says, He removed the stone... And the stone was not returned furthermore to its place.

Reb Moshe of Kobrin

The aforementioned, is referring to the “Lev ho’even” - stone heart, that the Yetzer Horah tries to clog one’s heart to deter him from Avodas Hashem.