Then I possibly have a crazy question. Wouldn't the freewoman (firstlings of his flock, the Lamb) come from Seth whom replaced Abel? And the bondwoman (flesh) come from Cain (fruit of the ground/ man's labor)? Wouldn't the bondwoman (under the mosaic Law) then also come from Ishmael instead of Isaac? I realize the promise was offered to Jews first, so I am still confused.
"And the angel of the Lord said unto her, Return to thy mistress,
and submit thyself under her hands." (Genesis 16:9) Hagar was told to return to her mistress; foreshadowing flesh and works of the mosaic Law submitting to grace? "And the angel of the Lord said unto her, Behold, thou art with child, and shalt bear a son, and shalt call his name Ishmael;
because the Lord hath heard thy affliction."(Ishmael meaning "God Listens").
"Nevertheless what saith the scripture? Cast out the bondwoman and her son: for the son of the bondwoman shall not be heir with the son of the freewoman." (Galatians 4:30)