'Unbelief' in the Bible

And He did not do many miracles there because of their unbelief.

And He wondered at their unbelief.And He was going around the villages teaching.

Immediately the boy’s father cried out and said, “I do believe; help my unbelief.”

Afterward He appeared to the eleven themselves as they were reclining at the table; and He reproached them for their unbelief and hardness of heart, because they had not believed those who had seen Him after He had risen.

What then? If some did not believe, their unbelief will not nullify the faithfulness of God, will it?

yet, with respect to the promise of God, he did not waver in unbelief but grew strong in faith, giving glory to God,

Quite right, they were broken off for their unbelief, but you stand by your faith. Do not be conceited, but fear;

And they also, if they do not continue in their unbelief, will be grafted in, for God is able to graft them in again.

even though I was formerly a blasphemer and a persecutor and a violent aggressor. Yet I was shown mercy because I acted ignorantly in unbelief;

So we see that they were not able to enter because of unbelief.