Musar su Salmi 62:13

[And according to the words of Rav, the words of the verse (Psalms 62:13) are well explained, viz.: “And Yours, O L-rd, is kindness; for You pay a man according to his works.” For many ask: “What kindness is there in the L-rd’s bestowing good for the fulfillment of his mitzvoth?” But according to this [interpretation of Rav], it is well understood. For it is known that if one would, with his wisdom, invent a machine with which the builders could build a city in one day, and news of this came to the king, he [the inventor] would certainly find favor in his eyes, and he would give him a great gift according to “the king’s hand,” but it is inconceivable that he would give him those cities that his servants built with this machine and call them by his name as if he himself had built them. But in this case, through the words of Torah that one learns in this world, the creation of heaven and earth is fulfilled, as we wrote above in Chapter I. Now, in truth, did the man himself build these palaces that they should be called by his name? Is it not the Holy One Blessed be He through His power and His strength, who, in His goodness, renews the creation every day and who Himself gives power to the words of Torah that he learned to be the foundation of this thing? And even so, the Holy One Blessed be He accounts it to him as if he himself had built the celestial and terrestrial palaces. And this is Rav’s intent in “as if he himself had planted the heavens and the earth.” And it is also possible to interpret the seemingly superfluous “You” [(in the Hebrew)] in the verse [“For You pay a man according to his works,”] in the manner of the GRA on (Mishlei 10:24): “The fear of the wicked one, it will come upon him, and the desire of the righteous, He will give.” For the transgression that a man commits, it itself will punish him, wherefore the punishment has a limit, just as the transgression itself has a limit. But, for the mitzvah, the Holy One Blessed be He pays him, by Himself and in His honor, wherefore the reward is eternal, without limit, just as the Holy One Blessed be He Himself is without limit. And this is the intent of the verse: “And Yours, O L-rd is kindness; for You pay a man according to his works.” That is, You Yourself pay a man reward for the fulfillment of his mitzvoth, so that there not be a limit to his reward.