Youcat commented through CCC – Question n. 335.

YOUCAT Question n. 335 - What significance does the Law of the Old Covenant have? 

(Youcat answer) In the Law (the Torah), and its centerpiece, the Ten Commandments (the decalogue), the will of God is manifested to the people of Israel; following the Torah is for Israel the central way to salvation. Christians know that we can tell by the Law what ought to be done. They also know, however, that it is not the Law that saves us.

A deepening through CCC

(CCC 1964 a) The Old Law is a preparation for the Gospel. "The Law is a pedagogy and a prophecy of things to come" (St. Irenaeus, Adv. haeres. 4, 15, 1: PG 7/1, 1012). It prophesies and presages the work of liberation from sin which will be fulfilled in Christ: it provides the New Testament with images, "types," and symbols for expressing the life according to the Spirit. Finally, the Law is completed by the teaching of the sapiential books and the prophets which set its course toward the New Covenant and the Kingdom of heaven. There were…  under the regimen of the Old Covenant, people who possessed the charity and grace of the Holy Spirit and longed above all for the spiritual and eternal promises by which they were associated with the New Law.

Reflecting and meditating 

(Youcat comment) Every man has the experience of finding that something good is, so to speak, “prescribed”. But one does not have the strength to accomplish it; it is too difficult; one feels “helpless” (see Rom 8:3 and Rom 7:14-25). One sees the Law and feels that one has been handed over to sin. And so precisely through the Law it becomes clear how urgently we rely on inner strength in order to fulfill the Law. That is why the Law, as good and important as it is, only prepares the way for faith in the saving God.

(CCC Comment)

(CCC 1964 b)  Conversely, there exist carnal men under the New Covenant still distanced from the perfection of the New Law: the fear of punishment and certain temporal promises have been necessary, even under the New Covenant, to incite them to virtuous works. In any case, even though the Old Law prescribed charity, it did not give the Holy Spirit, through whom "God's charity has been poured into our hearts" (St. Thomas Aquinas, STh I-II, 107, 1 ad 2; cf. Rom 5:5). (CCC 1981) The Law of Moses contains many truths naturally accessible to reason. God has revealed them because men did not read them in their hearts. (CCC 1982) The Old Law is a preparation for the Gospel.    

(The next question is: How did Jesus deal with the Law of the Old Covenant?)