'Unbelief' in the Bible

For what? if some have not believed, shall their unbelief make the faith of God of none effect?

and hesitated not at the promise of God through unbelief; but found strength in faith, giving glory to God;

Right: they have been broken out through unbelief, and thou standest through faith. Be not high-minded, but fear:

And they too, if they abide not in unbelief, shall be grafted in; for God is able again to graft them in.

For as indeed ye also once have not believed in God, but now have been objects of mercy through the unbelief of these;

For God hath shut up together all in unbelief, in order that he might shew mercy to all.