Rashi on Genesis 32:13/רש"י על בראשית ל״ב:י״ג

1היטב 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).

2ושמתי את זרעך כחול הים AND I WILL MAKE THY SEED AS THE SAND OF THE SEA — Where, indeed, did God promise him this? Did he not promise him only (Genesis 28:14) “And thy seed shall be as the dust of the earth"? But the explanation is that He had at the same time promised him (Genesis 28:15) “for I will not leave thee until I have done that which I have spoken about thee”, and to Abraham he had promised (Genesis 22:17) “and I will greatly multiply thy seed as the stars of heaven and as the sand which is upon the seashore”.