Ezekiel 3:7

5For you are not sent to a people of a strange speech and of a hard language, but to the house of Israel—

6not to many peoples of a strange speech and of a hard language, whose words you can’t understand. Surely, if I sent you to them, they would listen to you.

7But the house of Israel will not listen to you, for they will not listen to me; for all the house of Israel are obstinate and hard-hearted.

8Behold, I have made your face hard against their faces, and your forehead hard against their foreheads.

9I have made your forehead as a diamond, harder than flint. Don’t be afraid of them, neither be dismayed at their looks, though they are a rebellious house.”