You must be born again!

“You must be born again!”
John_3:1-21
John_3:2
Perhaps he came by night because he was busy all the day, or because he would make private inquiries before he committed himself to the new teacher. Jesus did not refuse him a midnight audience, and Nicodemus came to Him in courteous and candid spirit.
John_3:3
Thus he tried the faith which the inquiring ruler already had. The doctrine of regeneration has been a test question and a stone of stumbling to many; and always will be so. Jesus tried Nicodemus at the outset with this vital question, for He never suppresses truth to win followers.
John_3:4-6
Flesh at its best can only produce flesh; and since we must become spiritual in order to enter the spiritual kingdom of Jesus, it is inevitable that we must be born again, or else remain strangers to the things of God. Every man must be born twice or die twice: let this never be forgotten.
John_3:7-8
The regenerate man is a mystery, and whence his new nature came, and whither it tends, are both spiritual questions which the carnal mind is unable to answer.
John_3:10-12
earthly things or things belonging to this world
John_3:10-12
The higher truths are not opened up to those who are staggered by the simpler doctrines. It would be idle to attempt it.
John_3:13-13
It is remarkable that the same chapter which so strongly teaches us the need of the new birth is that which most clearly sets forth the gospel of faith in Christ Jesus. Both truths are to be cordially believed. We must be born again, and yet whosoever believe's in Jesus is not condemned.
John_3:18
Let this be well marked. All this family who have not believed are already condemned.
John_3:19-21
With such simple teaching before us, it will be terrible if any one of us should live and die in unbelief. 
It becomes us at once to believe in Jesus, for ere long we shall be gone where gospel promises are no longer presented as a ground of hope. 
Lord, we believe, and by grace we are saved.