Most of the time, I just keep my mouth shut re many of such arguments, because people are going to believe what they want to believe, but sometimes, I just can't remain silent. You have written here when you think this happened, but what biblical proof do you have for this?
In Hebrews, chapters 7 - 10, God's inspiration elaborates greatly on this issue. You may read it all for yourself, but I will pull a few main verses out for you.
Hebrews 7:
22 by so much more Jesus has become a surety of a better covenant.
Hebrews 8:
7
For if that first covenant had been faultless, then no place would have been sought for a second. 8 Because finding fault with them, He says: “Behold, the days are coming, says the Lord, when
I will make a new covenant with the house of Israel and with the house of Judah— 9 not according to the covenant that I made with their fathers in the day when I took them by the hand to lead them out of the land of Egypt; because
they did not continue in My covenant, and I disregarded them, says the Lord. 10 For
this is the covenant that I will make with the house of Israel after those days, says the Lord: I will put My laws in their mind and write them on their hearts; and I will be their God, and they shall be My people. 11 None of them shall teach his neighbor, and none his brother, saying, ‘Know the Lord,’ for all shall know Me, from the least of them to the greatest of them. 12 For I will be merciful to their unrighteousness, and their sins and their lawless deeds I will remember no more.”
13
In that He says, “A new covenant,” He has made the first obsolete. Now what is becoming obsolete and growing old is ready to vanish away.
Hebrews 9:
1 Then indeed, even the first
covenant had ordinances of divine service and the earthly sanctuary.
9 It
was symbolic for the present time in which both gifts and sacrifices are offered which cannot make him who performed the service perfect in regard to the conscience— 10
concerned only with foods and drinks, various washings, and fleshly ordinances imposed until the
time of reformation.
15 And for this reason He is the Mediator of the
new covenant, by means of death,
for the redemption of the transgressions under the first covenant, that those who are called may receive the promise of the eternal inheritance.
24 For Christ has not entered the holy places made with hands,
which are copies of the true, but into heaven itself, now to appear in the presence of God for us; 25
not that He should offer Himself often, as the high priest enters the Most Holy Place every year with blood of another— 26 He then would have had to suffer often since the foundation of the world;
but now, once at the end of the ages, He has appeared to
put away sin by the sacrifice of Himself.
Hebrews 10:
8 Previously saying, “Sacrifice and offering, burnt offerings, and
offerings for sin You did not desire, nor had pleasure
in them” (which are offered according to the law), 9 then He said, “Behold, I have come to do Your will, O God.”
He takes away the first that He may establish the second.
The new covenant does away with the old because Jesus finally, once and for all, has fulfilled the need for the sacrifice, so to follow the old means that one does not accept the new perfect sacrifice and that person is still in need of the perfect One.