Romans 11:32  For God hath concluded them all in unbelief, that he might have mercy upon all.

Matthew 13:58  And he did not many mighty works there because of their unbelief.

Matthew 17:20  And Jesus said unto them, Because of your unbelief: for verily I say unto you, If ye have faith as a grain of mustard seed, ye shall say unto this mountain, Remove hence to yonder place; and it shall remove; and nothing shall be impossible unto you.