6 “They have not been hidden from their sons in another generation”. This is our generation wherein there has been given to us regeneration. “Telling forth the praises of the Lord and His powers, and His wonderful works which He has done.” The order of the words is, “and our fathers have told unto us, telling forth the praises of the Lord.” The Lord is praised, in order that He may be loved. For what object can be loved more to our health? “And He has raised up a testimony in Jacob, and has set a law in Jacob”. This is the beginning whereof has been spoken above, “I will declare propositions from the beginning.” So then the beginning is the Old Testament, the end is the New. For fear does prevail in the law. “But the end of the law is Christ for righteousness to every one believing;” at whose bestowing “love is shed abroad in our hearts through the Holy Spirit, which has been given to us:” and love made perfect does cast out fear, inasmuch as now without the Law the righteousness of God has been made manifest. But inasmuch as He has a testimony by the Law and the Prophets, therefore, “He has raised up a testimony in Jacob.” For even that Tabernacle which was set up with a work so remarkable and full of such wondrous meanings, is named the Tabernacle of Testimony, wherein was the veil over the Ark of the Law, like the veil over the face of the Minister of the Law; because in that dispensation there were “parables and propositions.” For those things which were being preached and were coining to pass were hidden in veiled meanings, and were not seen in unveiled manifestations. But “when you shall have passed over unto Christ,” says the Apostle, “the veil shall be taken away.” For “all the promises of God in Him are yea, Amen.” Whosoever therefore does cleave to Christ, has the whole of the good which even in the letters of the Law he perceives not: but whosoever is an alien from Christ, does neither perceive, nor has. “He has set a law in Israel.” After his usual custom he is making a repetition. For “He has raised up a testimony,” is the same as, “He has set a law,” and “in Jacob,” is the same as “in Israel.” For as these are two names of one man, so law and testimony are two names of one thing. Is there any difference, says some one, between “has raised up” and “has set”? Yea indeed, the same difference as there is between “Jacob” and “Israel:” not because they were two persons, but these same two names were bestowed upon one man for different reasons; Jacob because of supplanting, for that he grasped the foot of his brother at his birth: but Israel because of the vision of God. So “raised up” is one thing, “set” is another. For, “He has raised up a testimony,” as far as I can judge, has been said because by it something has been raised up; “For without the Law,” says the Apostle, “sin was dead: but I lived sometime without the Law: but at the coming in of the commandment sin revived.” Behold that which has been raised up by the testimony, which is the Law, so that what was lying hidden might appear, as he says a little afterwards: “But sin, that it might appear sin, through a good thing has wrought in me death.” But “He has set a law,” has been said, as though it were a yoke upon sinners, whence has been said, “For upon a just man law has not been imposed.” It is a testimony then, so far forth as it does prove anything; but a law so far forth as it does command; though it is one and the same thing. Wherefore just as Christ is a stone, but to believers for the Head of the corner, while to unbelievers a stone of offense and a rock of scandal; so the testimony of the Law to them that use not the Law lawfully, is a testimony whereby sinners are to be convicted as deserving of punishment; but to them that use the same lawfully, is a testimony whereby sinners are shown unto whom they ought to flee in order to be delivered....
7. “How great things,” he says, “He has commanded our fathers, to make the same known to their sons?”. “That another generation may know, sons who shall be born and shall rise up, and they may tell to their sons”. “That they may put their hope in God, and may not forget the works of God, and may seek out His commandments”. “That they may not become, like their fathers, a crooked and embittering generation: a generation that has not guided their heart, and the spirit thereof has not been trusted with God”. These words do point out two peoples as it were, the one belonging to the Old Testament, the other to the New: for in that he says, he has implied that they received the commandments, “to make them known to their sons,” but that they did not know or do them: but they received them themselves, to the end “that another generation might know,” what the former knew not. “Sons who shall be born and shall arise.” For they that have been born have not arisen: because they had not their heart above, but rather on the earth. For the arising is with Christ: whence has been said, “If you have arisen with Christ, savour ye the things which are above.” “And they may tell them,” he says, “to their sons, in order that they may put their hope in God.”...“And may not forget the works of God:” that is to say, in magnifying and vaunting their own works, as though they did them themselves; while “God it is that works,” in them that work good things, “both to will and to work according to good will.” “And may search out His commandments.”...The commandments which He has commanded. How then should they still search out, whereas they have already learned them, save that by putting their hope in God, they do then search out His commandments, in order that by them, with His aid, they may be fulfilled? And he says why, by immediately subjoining, “and its spirit has not been trusted with God,” that is, because it had no faith, which does obtain what the Law does enjoin. For when the spirit of man does work together with the Spirit of God working, then there is fulfilled that which God has commanded: and this does not come to pass, except by believing in Him that does justify an ungodly man. Which faith the generation crooked and embittering had not: and therefore concerning the same has been said, “The spirit thereof has not been trusted with God.” For this has been said much more exactly to point out the grace of God, which does work not only remission of sins, but also does make the spirit of man to work together therewith in the work of good deeds, as though he were saying, his spirit has not believed in God. For to have the spirit trusted with God, is, not to believe that his spirit is able to do righteousness without God, but with God. For this is to believe in God: which is surely more than to believe God. For ofttimes we must believe even a man, though in him we must not believe. To believe in God therefore is this, in believing to cleave unto God who works good works, in order to work with Him well....
Source: The Enarrations, or Expositions, on the Psalms (New Advent)