It is obvious that the grace of the law of faith is greater than that of the law of Moses. For although the law of Moses was intended to be beneficial, it became the law of death because it was flouted. Then, because there was no way it could make provision for sinners to be saved, there came the law of faith, which not only forgives sinners but also makes them righteous. There is therefore a great deal of difference between one law and the other.
He said that the tables of Moses were of stone, as [also] they were written with letters; and that these were of flesh, I mean the hearts of the Apostles, and had been written on by the Spirit; and that the letter indeed killeth, but the Spirit giveth life. There was yet wanting to this comparison the addition of a further and not trifling particular, that of the glory of Moses; such as in the case of the New Covenant none saw with the eyes of the body. And even for this cause it appeared a great thing in that the glory was perceived by the senses; (for it was seen by the bodily eyes, even though it might not be approached;) but that of the New Covenant is perceived by the understanding.
Now by "ministration of death" he means the Law. And mark too how great the caution he uses in the comparison so as to give no handle to the heretics; for he said not, 'which causeth death,' but, "the ministration of death;" for it ministereth unto, but was not the parent of, death; for that which caused death was sin; but [the Law] brought in the punishment, and showed the sin, not caused it. For it more distinctly revealed the evil and punished it: it did not impel unto the evil: and it ministered not to the existence of sin or death, but to the suffering of retribution by the sinner. So that in this way it was even destructive of sin. For that which showeth it to be so fearful, it is obvious, maketh it also to be avoided. As then he that taketh the sword in his hands and cutteth off the condemned, ministers to the judge that passeth sentence, and it is not he that is his destruction, although he cutteth him off; nay, nor yet is it he who passeth sentence and condemneth, but the wickedness of him that is punished; so truly here also it is not that destroyeth, but sin. This did both destroy and condemn, but that by punishing undermined its strength, by the fear of the punishment holding it back.
For the Law was nothing else but letters: a certain succor was not found leaping forth from out the letters and inspiring them that combat, as is the case in Baptism; but pillars and writings bearing death to those who transgress the letters. Seest thou how in correcting the Jewish contentiousness, by his very expressions even he lessens its authority, speaking of stone and letters and a ministration of death, and adding that it was engraven? For hereby he declareth nothing else than this, that the Law was fixed in one place; not, as the Spirit, was present everywhere, breathing great might into all; or that the letters breathe much threatening, and threatening too which can not be effaced but remaineth for ever, as being engraved in stone. Then even whilst seeming to praise the old things, he again mixeth up accusation of the Jews. For having said, "written and engraven in stones, came with glory," he added, "so that the children of Israel could not look steadfastly upon the face of Moses;" which was a mark of their great weakness and grovelling spirit.
"How shall not rather the ministration of the Spirit be with glory?" for henceforth with confidence he extolleth the things of the New [Covenant] as indisputable. And observe what he doth. He opposed 'stone' to 'heart,' and 'letter' to 'spirit.' Then having shown the results of each, he doth not set down the results of each; but having set down the work of the latter, namely, death and condemnation, he setteth not down that of the spirit, namely, life and righteousness; but the Spirit Itself; which added greatness to the argument. For the New Covenant not only gave life, but supplied also 'The Spirit' Which giveth the life, a far greater thing than the life. Wherefore he said, "the ministration of the Spirit."
Since he called the law the ministry of death, it was natural to call the Gospel the ministry of life; but the apostle gave it a higher name – he called it the ministry of the Spirit. For the New Testament has the power to impart not only life, but – what is far more important – the Spirit Himself, who gives life. All the more glorious, then, is it in comparison with the law.
That the Old Testament is less than the New he proves in three ways. First, from its effect, because the former is a covenant of death, but the latter of life, as has been said. In regard to this he says, If the dispensation of death, i.e., the Old, which is the occasion of death; and this corresponds to what he said, namely, that the written code kills, but the Spirit gives life. Secondly, as to the way it was delivered, for the Old was delivered written on stone tablets, but the New was impressed by the Spirit on human hearts. He suggests this when he says, carved in letters, i.e., perfectly formed, on stone, i.e., on tablets of stone. This corresponds to his statement, not in a written code but in the Spirit. Thirdly, as to perfection: for the glory of the Old Testament is without assurance, because the Law brought no one to perfection. But in the New there is glory with the hope of a better glory, i.e., eternal: "My salvation will be forever" (Is. 51:6). This is suggested when he says, fading as this was: "If you receive circumcision, Christ will be of no advantage to you" (Gal. 5:2). He states the conclusion when he says, will not the dispensation of the Spirit be attended with greater glory? which is plain.
[AD 384] Ambrosiaster on 2 Corinthians 3:8