John 8:27

They did not understand that he meant the Father,

John 8:43

"How is it that you do not understand what I say? It is because you cannot listen to my message.

John 8:47

"He who is from God listens to God's words. For this reason you do not listen, because you are not from God."

Romans 11:7-10

What then? that which Israel has been seeking for, that he has not obtained; but the chosen have obtained it, and the rest have been hardened.

2 Corinthians 4:3-4

But even if my gospel, too, is "veiled," it is among those who are on the way to perish that it is "veiled."

Treasury of Scripture Knowledge

Summary

They understood not that he spake to them of the Father.

Bible References

General references

John 8:43
"How is it that you do not understand what I say? It is because you cannot listen to my message.
Romans 11:7
What then? that which Israel has been seeking for, that he has not obtained; but the chosen have obtained it, and the rest have been hardened.
2 Corinthians 4:3
But even if my gospel, too, is "veiled," it is among those who are on the way to perish that it is "veiled."