Nic tried to re-up his carnal perspective, to focus back on the birth from his mother's womb. Jesus took Him to a 'higher calling', being born from above, spiritual birth. What is spiritual birth? well, it is the dead spirit in the fallen man being born by the Life of God entering the cleansed spirit, to be there as witness that we are in His family thereafter.
The dead spirit of man is cleansed by the sacrifice made for us on the Cross. The Passover lamb was slain to atone then a small portion of the blood --the rest of which was 'poured out upon the earth', the largest altar upon which are smaller altars-- was placed upon the doorposts and lintel for the angel of death to pass over. The blood of Jesus upon the entry to our spirit is signal that we are under His covering of the law of sin and death, no longer subject to the 600+ laws of Moses.
BUT as family members we are to be raised up in the Way that we should go as family members. Who is going to do this parenting thing? The indwelling spirit of God, as the earnest of our inheritance, The Holy Spirit. Is there some way to know what the parameters of this family behavior are? well, yes there is. Jesus explained it as Two Great Commandments upon which hang all the law and the Prophets:
Jesus said unto him, Thou shalt love the Lord thy God with all thy heart, and with all thy soul, and with all thy mind. This is the first and great commandment. And the second is like unto it, Thou shalt love thy neighbour as thyself. On these two commandments hang all the law and the prophets. [Matt 22:37-40]