There. You have it. Thank you.
Heb 8:13 In that he saith, A new covenant, he hath made the first old. Now that which decayeth and waxeth old is ready to vanish away.
Just as the old covenant will be replaced by the new.
Jer 31:31-32
31 Behold, the days come, saith the Lord, that I will make a new covenant with the house of Israel, and with the house of Judah:
32 Not according to the covenant that I made with their fathers in the day that I took them by the hand to bring them out of the land of Egypt; which my covenant they brake, although I was an husband unto them, saith the Lord:
The new covenant and the old covenant cannot exist at the same time. Just as daylight and dark are not coexistent:
John 1:4-5
4 In him was life; and the life was the light of men.
5 And the light shineth in darkness; and the darkness comprehended it not.
John 8:12 Then spake Jesus again unto them, saying, I am the light of the world: he that followeth me shall not walk in darkness, but shall have the light of life.
I hope you are not one that would die rather than change your doctrine when your doctrine is proved false.