Jesus Christ took upon Himself the flesh of a man and will forever be in a body of a man because... He has become a man!
He is the God Man, the first born from the dead (separation from God), glorified and raise up to sit at God the Father's right hand.
The New Covenant is between the God Man Jesus and the Father and it is in fact indestructible and cannot fail.
Only those that abide IN Christ until the end of their lives... will receive the Lord's reward, all others will receive the devil's reward.
What does these passages say?
Jeremiah 31:31-34
Behold, the days are coming, declares the Lord, when I will make a new covenant with the house of Israel and the house of Judah, not like the covenant that I made with their fathers on the day when I took them by the hand to bring them out of the land of Egypt, my covenant that they broke, though I was their husband, declares the Lord. For this is the covenant that I will make with the house of Israel after those days, declares the Lord: I will put my law within them, and I will write it on their hearts. And I will be their God, and they shall be my people. And no longer shall each one teach his neighbor and each his brother, saying, ‘Know the Lord,’ for they shall all know me, from the least of them to the greatest, declares the Lord (Yahweh.) For I will forgive their iniquity, and I will remember their sin no more.
I will post these passages in hope that they will help in understanding things about the New Covenant. I know that there will be blockage in some eyes who cling to past teachings, but this is a discussion forum, and these deserve consideration.
Jn 3:34
For he whom God has sent utters the words of God, for he gives the Spirit without measure (unto Him.)
Yeshua was born a man, but a man who had the fullness of God's spirit.
Ga 4:4–5
But when the fullness of time had come, God sent forth his Son, born of woman (,) born under the law, to redeem those who were under the law, so that we might receive adoption as sons.
It is a complex matter to understand how Yeshua was able to do the things He did without committing sin. The Pharisees could not understand it, but if we acknowledge that punctuation was not in the original manuscripts and remove the comma after the word "woman," it simplifies our understanding. Yeshua WAS the New Covenant and not born under the Old Covenant. I have attached the verse from an interlinear to show that it should have read "born of woman having been born under the law."
To add clarity, I inserted the name of God BACK INTO the verses here.
Is 42:6–8
I am the LORD (Yahweh); I have called you in righteousness; I will take you by the hand and keep you; I will give you as a covenant for the people, a light for the nations, to open the eyes that are blind, to bring out the prisoners from the dungeon, from the prison those who sit in darkness. I am the LORD (Yahweh); that is my name; my glory I give to no other, nor my praise to carved idols.
Is 49:8–9
Thus says the LORD (Yahweh): “In a time of favor I have answered you; in a day of salvation I have helped you; I will keep you and give you as a covenant to the people, to establish the land, to apportion the desolate heritages, saying to the prisoners, ‘Come out,’ to those who are in darkness, ‘Appear.’ "
Now, my view is that Yeshua was born a son of Yahweh to BE the New Covenant as promised in Isaiah. That really simplifies our understand when He told his disciples "this is my blood of the New Covenant." He was between Yahweh and man.