Ezekiel 3:7-9

But the people of Israel are not willing to listen to you because they are not willing to listen to me, for all the Israelites are hardened and obstinate. But I will make you as unyielding and hardened as they are. I will make your forehead like the hardest stone, harder than flint. Do not be afraid of them or terrified by them, though they are a rebellious people.”