'Hard' 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.

Son of man, Nebuchadrezzar king of Babylon caused his army to do hard service against Tyre; every head was made bald, and every shoulder was peeled: yet had he from Tyre no wages, nor his army, for the service that he had served against it.