John 12:39

This is why they could not believe: Isaiah also said,

John 5:44

How can you believe when you accept each other's praise and do not look for the praise that comes from the only God?

Isaiah 6:9-10

"Go!" he responded. "Tell this people: ""Keep on hearing, but do not understand; keep on seeing, but do not perceive.'

Isaiah 44:18-20

They don't realize; they don't understand, because their eyes are plastered over so they cannot see, and their minds, too, so they cannot understand.

John 6:44

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

John 10:38

But if I'm doing them, even though you don't believe me, believe the actions, so that you may know and understand that the Father is in me and I am in the Father."

2 Peter 2:14

With eyes full of adultery, they cannot get enough of sin. They seduce unsteady souls and have had their hearts expertly trained in greed. They are doomed to a curse.

Treasury of Scripture Knowledge

Summary

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

Bible References

They

John 5:44
How can you believe when you accept each other's praise and do not look for the praise that comes from the only God?
John 6:44
No one can come to me unless the Father who sent me draws him, and I will raise him to life on the last day.
John 10:38
But if I'm doing them, even though you don't believe me, believe the actions, so that you may know and understand that the Father is in me and I am in the Father."
Isaiah 44:18
They don't realize; they don't understand, because their eyes are plastered over so they cannot see, and their minds, too, so they cannot understand.
2 Peter 2:14
With eyes full of adultery, they cannot get enough of sin. They seduce unsteady souls and have had their hearts expertly trained in greed. They are doomed to a curse.

General references

Exodus 10:20
But the LORD made Pharaoh's heart stubborn and he would not let the Israelis go.
Deuteronomy 29:4
Yet to this day, the LORD hasn't given you a heart that understands, eyes that perceive, and ears that discern.
John 1:5
And the light shines on in the darkness, and the darkness has never put it out.
John 9:18
The Jewish leaders did not believe that the man had been blind and had gained sight until they summoned his parents
John 10:37
If I'm not doing my Father's actions, don't believe me.

International Standard Version Copyright © 1996-2008 by the ISV Foundation.