Now the end of every law is to make men righteous and virtuous, as was stated above (Q. 92, A. 1):  and consequently the end of the Old Law was the justification of men.  The Law, however, could not accomplish this:  but foreshadowed it by certain ceremonial actions, and promised it in words.  And in this respect, the New Law fulfils the Old by justifying men through the power of Christ’s Passion.  This is what the Apostle says (Rom. 8:3, 4):  “What the Law could not do . . .  God sending His own Son in the likeness of sinful flesh . . . hath condemned sin in the flesh, that the justification of the Law might be fulfilled in us.”  And in this respect, the New Law gives what the Old Law promised, according to 2 Cor. 1:20:  “Whatever are the promises of God, in Him,” i.e. in Christ, “they are ’Yea’.” [The Douay version reads thus:  “All the promises of God are in Him, ’It is’.”] Again, in this respect, it also fulfils what the Old Law foreshadowed.  Hence it is written (Col. 2:17) concerning the ceremonial precepts that they were “a shadow of things to come, but the body is of Christ”; in other words, the reality is found in Christ.  Wherefore the New Law is called the law of reality; whereas the Old Law is called the law of shadow or of figure.

Now Christ fulfilled the precepts of the Old Law both in His works and in His doctrine.  In His works, because He was willing to be circumcised and to fulfil the other legal observances, which were binding for the time being; according to Gal. 4:4:  “Made under the Law.”  In His doctrine He fulfilled the precepts of the Law in three ways.  First, by explaining the true sense of the Law.  This is clear in the case of murder and adultery, the prohibition of which the Scribes and Pharisees thought to refer only to the exterior act:  wherefore Our Lord fulfilled the Law by showing that the prohibition extended also to the interior acts of sins.  Secondly, Our Lord fulfilled the precepts of the Law by prescribing the safest way of complying with the statutes of the Old Law.  Thus the Old Law forbade perjury:  and this is more safely avoided, by abstaining altogether from swearing, save in cases of urgency.  Thirdly, Our Lord fulfilled the precepts of the Law, by adding some counsels of perfection:  this is clearly seen in Matt. 19:21, where Our Lord said to the man who affirmed that he had kept all the precepts of the Old Law:  “One thing is wanting to thee:  If thou wilt be perfect, go, sell whatsoever thou hast,” etc. [St. Thomas combines Matt. 19:21 with Mk. 10:21].

Reply Obj. 1:  The New Law does not void observance of the Old Law except in the point of ceremonial precepts, as stated above (Q. 103, AA. 3, 4).  Now the latter were figurative of something to come.  Wherefore from the very fact that the ceremonial precepts were fulfilled when those things were accomplished which they foreshadowed, it follows that they are no longer to be observed:  for if they were to be observed, this would mean that something is still to be accomplished and is not yet fulfilled.  Thus the promise of a future gift holds no longer when it has been fulfilled by the presentation of the gift.  In this way the legal ceremonies are abolished by being fulfilled.