they.

John 5:44
How can you believe if you accept glory from one another, yet do not seek the glory 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 up at the last day.

John 10:38
But if I am doing them, even though you do not believe Me, believe the works themselves, so that you may know and understand that the Father is in Me, and I am in the Father."

Isaiah 44:18-20
They cannot comprehend or understand, for He has shut their eyes so they cannot see, and closed their minds so they cannot understand. . . .

2 Peter 2:14
Their eyes are full of adultery; their desire for sin is never satisfied; they seduce the unstable. They are accursed children with hearts trained in greed.

because.

Isaiah 6:9, 10
And He replied, "Go and tell this people: 'Be ever hearing, but never understanding; be ever seeing, but never perceiving.' . . .