Does the New Covenant make the Old Covenant obsolete:

In the Old Covenant, salvation was found by looking forward to the death of Christ (see: How were people saved in the Old Testament). In the New Covenant, salvation is found by looking back the death of Christ. For this reason, Paul calls the Old Covenant obsolete; replaced by the New Covenant:

By calling this covenant “new,” he has made the first one obsolete; and what is obsolete and outdated will soon disappear. – (Hebrews 8:13)

The New Covenant is the fulfillment of the Old Covenant. We are found guilty of sin by the Old Covenant (the Laws of Moses). The New Covenant is our eternal salvation found by accepting the death of Christ.

For this reason Christ is the mediator of a new covenant, that those who are called may receive the promised eternal inheritance-now that he has died as a ransom to set them free from the sins committed under the first covenant.

Hebrews 9:15