'Forehead' in the Bible

But the house of Israel will not hearken unto thee, for none of them will hearken unto me. For all the house of Israel are hard of forehead and stiff of heart.

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

As an adamant harder than flint have I made thy forehead. Fear them not, neither be dismayed at them, for they are a rebellious house.