John 8:27

They did not know that He spoke to them concerning the Father.

John 8:43

Wherefore do you not understand my speech? Because you are not able to hear my word.

John 8:47

The one being of God hears the words of God: on account of this you do not hear, because you are not of God.

Romans 11:7-10

What then? Israel did not attain that which he was seeking, but the election obtained it, and the rest were hardened:

2 Corinthians 4:3-4

But if indeed our gospel is hidden, it is hidden with those who are lost:

Treasury of Scripture Knowledge

Summary

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

Bible References

General references

John 8:43
Wherefore do you not understand my speech? Because you are not able to hear my word.
Romans 11:7
What then? Israel did not attain that which he was seeking, but the election obtained it, and the rest were hardened:
2 Corinthians 4:3
But if indeed our gospel is hidden, it is hidden with those who are lost: