John 3:4
Nicodemus said to him, How can a man be born when he is old? can he become an unborn infant of his mother a second time, and be born?
John 3:3
Jesus answered and said to him, I tell you most truly, unless one has been born again he cannot see the kingdom of God.
John 4:11-12
The woman said to him, Sir, you have nothing to draw with, and the well is deep; whence then have you the living water?
John 6:53
Then Jesus said to them, I tell you most truly, unless you eat the flesh of the Son of man and drink his blood, you have no life in you.
John 6:60
Then many of his disciples hearing him said, This is a hard saying; who can hear him?
1 Corinthians 1:18
For the word of the cross is to the lost foolishness, but to the saved the power of God.
1 Corinthians 2:14
But the natural man receives not the [things] of the Spirit of God, for they are foolishness to him, and he cannot know them, for they are spiritually discerned.