Rashi, on Gen 32:13

“And when he had slept there that night, he set apart, of the things which he had, presents for his brother Esau.”

“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). ושמתי 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”.”

Imported from an open dataset — not yet checked against the printed edition.