Hebrews 8:7

For if the first covenant had been faultless, there could have been no room for a second one.

Hebrews 7:11

Now if perfection had been reached through the Levitical priesthood -- for on it as a basis even the law was enacted for the people-- what further need would there have been of appointing a different priest, with the rank of Melchizedek, instead of designating one with the rank of Aaron?

Hebrews 7:18

Indeed, the rescinding of a previous regulation takes place, because it was weak and ineffective --

Galatians 3:21

Is the law then contrary to God's promises? Of course not. For if a law had been given that was able to impart life, surely, then, right standing would have come through law.

Hebrews 8:6

But, as the case with Him now stands, He has entered upon a priestly service as much superior to theirs as the covenant of which He is the Mediator is superior to theirs, superior because it has been enacted upon superior promises.

Treasury of Scripture Knowledge

Summary

For if that first covenant had been faultless, then should no place have been sought for the second.

Bible References

Had

Hebrews 8:6
But, as the case with Him now stands, He has entered upon a priestly service as much superior to theirs as the covenant of which He is the Mediator is superior to theirs, superior because it has been enacted upon superior promises.
Hebrews 7:11
Now if perfection had been reached through the Levitical priesthood -- for on it as a basis even the law was enacted for the people-- what further need would there have been of appointing a different priest, with the rank of Melchizedek, instead of designating one with the rank of Aaron?
Galatians 3:21
Is the law then contrary to God's promises? Of course not. For if a law had been given that was able to impart life, surely, then, right standing would have come through law.