John 12:39

Therefore they could not believe, because Isaiah said again,

John 5:44

How can ye believe, who take glory one from another, and seek not the glory that comes only from God?

Isaiah 6:9-10

Then he said, Go and tell this people, Hear indeed, but do not understand; and see indeed, but do not perceive.

Isaiah 44:18-20

They did not know nor understand; for he has anointed their eyes that they not see and their hearts that they not understand.

John 6:44

No one can come to me unless the Father who has sent me draws him, and I will raise him up in the last day.

John 10:38

But if I do, though ye do not believe me, believe the works that ye may know and believe that the Father is in me and I in him.

2 Peter 2:14

having their eyes full of adultery, and not knowing how to cease from sin, baiting unstable souls, having their heart exercised in covetous practices; cursed sons,

Treasury of Scripture Knowledge

Summary

Therefore they could not believe, because that Esaias said again,

Bible References

They

John 5:44
How can ye believe, who take glory one from another, and seek not the glory that comes only from God?
John 6:44
No one can come to me unless the Father who has sent me draws him, and I will raise him up in the last day.
John 10:38
But if I do, though ye do not believe me, believe the works that ye may know and believe that the Father is in me and I in him.
Isaiah 44:18
They did not know nor understand; for he has anointed their eyes that they not see and their hearts that they not understand.
2 Peter 2:14
having their eyes full of adultery, and not knowing how to cease from sin, baiting unstable souls, having their heart exercised in covetous practices; cursed sons,

General references

Exodus 10:20
But the LORD hardened Pharaoh's heart, so that he would not let the sons of Israel go.
Deuteronomy 29:4
Yet the LORD has not given you a heart to perceive and eyes to see and ears to hear until today.
John 1:5
And the light shines in the darkness, and the darkness apprehended it not.
John 9:18
But the Jews did not believe concerning him that he had been blind and received his sight until they called the parents of him that had received his sight.
John 10:37
If I do not do the works of my Father, do not believe me.