Kommentar zu Bereschit 32:13

היטב איטיב I WILL SURELY DO [THEE] GOOD — The use of two words denoting “doing good” is intended to signify: היטב doing good to thee on account of your own merits, איטיב I will also do good to thee on account of your father’s merits (Genesis Rabbah 76:7).

AND THOU SAIDST: I WILL SURELY DO THEE GOOD. Even though he was afraid lest the sin cause him to lose that which he was promised, Jacob said: “You have done great kindnesses for me even though I was unworthy of them. Certainly You will do for me this undeserved kindness which You have promised me, namely, that You will bestow good upon me and increase my seed. My sin should not withhold from me the good You have promised me, for in the beginning I was also unworthy of it had You marked against me mine iniquities.³⁵See Psalms 130:3. And You did not promise it to me on account of my deeds, but only out of Your abundant mercies.”
And some commentators say³⁶Ibn Ezra. Thus Jacob’s fear was not lest his sin cause him to lose that which he was promised, but because he did not know, etc., as explained in the text. that Jacob had compassion for his children and household lest Esau smite them, because he did not know whether the promise, And thy seed shall be as the dust of the earth,³⁷Above, 28:14. applied to these or to others, it being possible that he himself would escape and have additional children. But in my opinion this is not correct, for if this was his thought, how did he say in his prayer, And Thou saidst: I will surely do thee good and make thy seed as the sand of the sea? Moreover, it was told to him in Beth-el, And behold, I am with thee, and will keep thee whithersoever thou goest, and I will bring thee back into this land.²⁶Above, 28:15. If his children were to fall before his brother’s sword, this promise would not be fulfilled, and it is to this promise that Jacob alluded when he said, And Thou saidst: I will surely do thee good. Similarly with the promise, And I will do thee good:²⁸Verse 10 here. all this Jacob said on the basis of it having been said to him, And I will be with thee.²⁷Ibid., 31:3. But all his misgivings were on account of the fear of sin, for it is the way of the righteous to be always fearful. Thus Jacob was fearful that perhaps even after he left Haran, he sinned by entering into a covenant with Laban, who was an idol-worshipper, or in some other matter, and Who can discern errors?³⁸Psalms 19:13.