John 8:27

They did not perceive that He was speaking to them of the Father.

John 8:43

How is it you do not understand me when I speak? It is because you cannot bear to listen to my words.

John 8:47

He who is a child of God listens to God's words. You do not listen to them: and why? It is because you are not God's children."

Romans 11:7-10

How then does the matter stand? It stands thus. That which Israel are in earnest pursuit of, they have not obtained; but God's chosen servants have obtained it, and the rest have become hardened.

2 Corinthians 4:3-4

If, however, the meaning of our Good News has been veiled, the veil has been on the hearts of those who are on the way to perdition,

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 you do not understand me when I speak? It is because you cannot bear to listen to my words.
Romans 11:7
How then does the matter stand? It stands thus. That which Israel are in earnest pursuit of, they have not obtained; but God's chosen servants have obtained it, and the rest have become hardened.
2 Corinthians 4:3
If, however, the meaning of our Good News has been veiled, the veil has been on the hearts of those who are on the way to perdition,