Midrash su Salmi 40:6

And his eyes were dim. Why did his vision become impaired? The Holy One, blessed be He, foresaw that Isaac would desire to bless Esau, and He decreed, therefore, that his sight should become weak so that when Jacob approached him for the blessing, Isaac would not realize that he was conferring the blessing upon Jacob. David proclaimed: Many things hast Thou done, O Lord, my God, even Thy wondrous works and Thy thoughts toward us. There is none to be compared unto Thee (Ps. 40:6). That is, all Thy wondrous works and Thy thoughts toward us are in our behalf.

(Exodus, Ibid.) "working wonders": It is not written "worked wonders," but "working wonders" — in time to come, viz. (Jeremiah 16:14) "Therefore, behold, days are coming, says the L rd, when it will no more be said 'As the L rd lives, who brought up the children of Israel from the land of Egypt,' but etc." Variantly: "working wonders": He wrought wonders for us and He does so in each generation, viz. (Psalms 139:14) "I shall thank You, for I have been wondrously wrought," and (Ibid. 40:6) "Many things) have You done — You, O L rd, my G d, etc." Variantly: "working wonders" with the fathers, and destined to work them with the sons, viz. (Michah 7:15) "As in the days when you went forth from the land of Egypt, I shall show him wonders." I will show him what I did not show the fathers. The miracles and the mighty acts that I am destined to perform for the sons are greater than those which I wrought for the fathers. And thus is it written (Psalms 22:18) "He works wonders" (as opposed to the singular "wonder" here), and (I Chronicles 16:36) "Blessed is the L rd, the G d of Israel, from world to world."

(Gen. 5:1:) THIS IS THE BOOK…. What did the Holy One do to Adam? He cast a sleep upon him and showed him Noah and all the unblemished, Abraham and all the proselytes, Isaac and all who sacrifice burnt offerings, Jacob and all tent dwellers, Moses and all the humble, Aaron and all the priests, Joshua and all the community leaders, David and all the kings, [Solomon and all the Judges]. Then, when he had seen them all, he awakened from his sleep. The Holy One said to him: Have you seen [these? By your life], all these righteous [are] coming forth from you. When he had told him this, his spirit was at rest. David said: Sovereign of the World, you have written me into the book of the first Adam, as stated (in Ps. 40:8 [7]): THEN SAID I: LO, I HAVE COME. IN THE SCROLL OF THE BOOK IT IS WRITTEN CONCERNING ME. Therefore I must utter a song to you, since it is stated: THEN SAID I. Now THEN can only be A SONG [according to what is stated (in Exod. 15:1): MOSES SANG THEN].⁹⁵THEN is understood as the object of the verb SANG. < David > therefore praises⁹⁶Gk.: kalos. him (in Ps. 40:6 [5]): YOU HAVE DONE MANY THINGS, O LORD MY GOD. When should we utter a song to you? In the world to come, as stated (in Ps. 98:1): A PSALM. O SING TO THE LORD A NEW SONG.