'Harder' in the Bible

And the hand of the people of Israel bore harder and harder on Jabin the king of Canaan, until they destroyed Jabin king of Canaan.

A brother offended is harder to be won than a strong city; and contentions are as the bars of a palace.

Jehovah, are not thine eyes upon fidelity? Thou hast smitten them, but they are not sore; thou hast consumed them, they have refused to receive correction: they have made their faces harder than a rock; they have refused to return.

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.