Rebekah's Two Nations
Isaac's birth was the result of a miracle from the LORD to elderly Abraham and Sarah:
"18:11 Now Abraham and Sarah were old and well stricken in age; and it ceased to be with Sarah after the manner of women. 18:12 Therefore Sarah laughed within herself, saying, After I am waxed old shall I have pleasure, my lord being old also? 18:13 And the LORD said unto Abraham, Wherefore did Sarah laugh, saying, Shall I of a surety bear a child, which am old? 18:14 Is any thing too hard for the LORD? At the time appointed I will return unto thee, according to the time of life, and Sarah [see Abram and Sarai] shall have a son." (Genesis 18:11-14 KJV)
"Two nations are in thy womb"
As it happened, Abraham and Sarah's son Isaac and his wife Rebekah also found themselves childless after marriage (although for some other reason than old age). In answer to their prayer, the LORD not only gave them one child, but two.
"25:21 And Isaac entreated the LORD for his wife, because she was barren: and the LORD was entreated of him, and Rebekah his wife conceived.
Esau and Jacob were twins - fraternal twins, definitely not identical, in either appearance or temperament.
"25:24 And when her days to be delivered were fulfilled, behold, there were twins in her womb.
The competition between Jacob and Esau began even before they were born ("25:22 And the children struggled together within her" Genesis 25:22 KJV) and continued into their adulthood. Then came the well-known incident of Esau selling his firstborn birthright to his younger brother Jacob for nothing more than a bowl of stew.
"25:27 And the boys grew: and Esau was a cunning hunter, a man of the field; and Jacob was a plain man, dwelling in tents [note: in that regard there is some similarity between the brothers Esau and Jacob and the brothers Cain and Abel; as well as the elder seeking to kill the younger out of jealousy - see My Brother's Shepherd] . 25:28 And Isaac loved Esau, because he did eat of his venison: but Rebekah loved Jacob.
Fact Finder: Did Jacob and Esau ever make peace with one another? When?