THE NEW BIRTH
The Spiritual birth spoken of in the previous verse is not of blood. It is not on the basis of lineage or Jewish heritage. It is not of the will of the flesh or a carnal desire, It is not of the will of man or human in it's origin.
IT IS OF GOD
THIS BIRTH IS SUPER NATURAL
When it is said that He will not cast them out the meaning is,
He will receive them, and give them all that which they come to Him for.
That the Father will, without fail, bring all those to Him in DUE time that were given Him.
John 6: 28-59.
In verse 37: He here assures us that this shall be done; all that the Father giveth Me SHALL come to Me [election described].