Hebrews 8:7

7.For if that first, etc. He confirms what he had said of the excellency of the covenant which God has made with us through Christ; and he confirms it on this ground, because the covenant of the Law was neither valid nor permanent; for if nothing was wanting in it, why was another substituted for it? But another has been substituted; and from this it is evident that the old covenant was not in every respect perfect. To prove this he adduces the testimony of Jeremiah, which we shall presently examine.

But it seems hardly consistent to say, that after having said that no place would have been sought for the second covenant, had the first been faultless, he should then say that the people were at fault, and that for this cause the new covenant was introduced as a remedy; and thus it appears unjust, that if the blame was in the people it should be transferred to God’s covenant. Then the argument seems not valid, for though God might have a hundred times blamed the people, yet the covenant could not on that account be deemed faulty. The answer to this objection may be easily given. Though the crime of violating the covenant was justly imputed to the people, who had through their own perfidy departed from God, yet the weakness of the covenant is also pointed out, because it was not written in their hearts. Then, to render it perfect and valid, God declares that it needed an amendment. It was not, therefore, without reason that the Apostle contended that a place was to be sought for a second. (132)