Why were the hearts of the Children of Israel described as being harder than stones in the noble verse: "Then your hearts became hardened after that, being like stones or even harder"?

The hearts of the Children of Israel were described as being harder than stones, exaggerating the severity of their hardness, because a stone may crack, whereas their hearts did not accept admonition. This is evidenced by their killing of prophets, their denial of messengers, their breaking of God's covenant, their distortion of His scriptures, and their betrayal of the Messenger (peace be upon him). Allah clarified that their punishments came because of their breaking of the covenant and the hardness of their hearts, warning the believers against imitating them and having hard hearts.