In biblical days as like in many countries and cultures today the birthright was considered when inherences and were involved. These considerations basically fell to the male children of the family as the female were considered to part of their husband's family. The first born male child would receive the "rights" of the birthright and a double portion the other son's would share as per the father's instructions.
Deuteronomy 21:15-17 15If a man have two wives, one beloved, and another hated, and they have born him children, both the beloved and the hated; and if the firstborn son be hers that was hated: 16Then it shall be, when he maketh his sons to inherit that which he hath, that he may not make the son of the beloved firstborn before the son of the hated,which is indeed the firstborn: 17But he shall acknowledge the son of the hated for the firstborn, by giving him a double portion of all that he hath: for he is the beginning of his strength; the right of the firstborn is his.
The birthright, in ancient Near Eastern culture, was a position of honor ad authority bestowed upon the firstborn son. It included a double portion of the inheritance and the leadership of the family. It was often associated with the continuation of God's covenantal promises. In the case of Jacob, acquiring the birthright positioned him as the heir to the Abrahamic covenant, through which all nations would be blessed. The birthright also carried spiritual implications..
Genesis 12:1 Now the LORD had said unto Abram, Get thee out of thy country, and from thy kindred, and from thy father's house, unto a land that I will shew thee: 2And I will make of thee a great nation, and I will bless thee, and make thy name great; and thou shalt be a blessing: 3And I will bless them that bless thee, and curse him that curseth thee: and in thee shall all families of the earth be blessed.
In Genesis 25 Esau thought very little about his birthright and sold it for a bowl of soup.
Genesis 25:31-34 31And Jacob said, Sell me this day thy birthright. 32And Esau said, Behold, I am at the point to die: and what profit shall this birthright do to me? 33And Jacob said, Swear to me this day; and he sware unto him: and he sold his birthright unto Jacob. 34Then Jacob gave Esau bread and pottage of lentiles; and he did eat and drink, and rose up, and went his way: thus Esau despised his birthright.
Ruben Israel's first born lost his birthright for the disrespect and contempt he showed towards his father, and it was given to another.
1 Chronicles 5:1-2 1Now the sons of Reuben the firstborn of Israel, (for he was the firstborn; but, forasmuch as he defiled his father's bed, his birthright was given unto the sons of Joseph the son of Israel: and the genealogy is not to be reckoned after the birthright. 2For Judah prevailed above his brethren, and of him came the chief ruler; but the birthright was Joseph's:)
Ruben slept with one of his father's, Israel wives forfeiting his right to the birthright and the corresponding blessing.
In turn it was conferred to Joseph and by way of extension his two sons the firstborn Manasseh and his brother Ephraim for Israel claimed them as his own so they could share in the inheritance.
Genesis 48:1-6 1And it came to pass after these things, that one told Joseph, Behold, thy father is sick: and he took with him his two sons, Manasseh and Ephraim. 2And one told Jacob, and said, Behold, thy son Joseph cometh unto thee: and Israel strengthened himself, and sat upon the bed. 3And Jacob said unto Joseph, God Almighty appeared unto me at Luz in the land of Canaan, and blessed me, 4And said unto me, Behold, I will make thee fruitful, and multiply thee, and I will make of thee a multitude of people; and will give this land to thy seed after thee for an everlasting possession. 5And now thy two sons, Ephraim and Manasseh, which were born unto thee in the land of Egypt before I came unto thee into Egypt, are mine; as Reuben and Simeon, they shall be mine. 6And thy issue, which thou begettest after them, shall be thine, and shall be called after the name of their brethren in their inheritance..
Israel adopted Joseph's two sons into the family as his own each receiving an allotted portion, as forming two distinct tribes in Israel.
In 1 Chronicles 5:1 we learn that the genealogy was not reckoned after the birthright meaning Ruben for he was Israel's firstborn.
Verse two tells us that Judah prevailed above his brethren, and of him came the chief ruler; but the birthright was Joseph's :)
One commentary notes "the genealogy was not to be reckoned after the birthright," but with a reference to a superior honor and privilege that had been conferred on Judah—not the man, but the tribe, whereby it was invested with the pre-eminence over all the other tribes, and out of it was to spring David with his royal lineage, and eventually the Messiah.
This is enumerated in the book of Hebrews.
Hebrews 7:1-17 1 For this Melchisedec, king of Salem, priest of the most high God, who met Abraham returning from the slaughter of the kings, and blessed him; 2To whom also Abraham gave a tenth part of all; first being by interpretation King of righteousness, and after that also King of Salem, which is, King of peace; 3Without father, without mother, without descent, having neither beginning of days, nor end of life; but made like unto the Son of God; abideth a priest continually. 4Now consider how great this man was, unto whom even the patriarch Abraham gave the tenth of the spoils. 5And verily they that are of the sons of Levi, who receive the office of the priesthood, have a commandment to take tithes of the people according to the law, that is, of their brethren, though they come out of the loins of Abraham: 6But he whose descent is not counted from them received tithes of Abraham, and blessed him that had the promises. 7And without all contradiction the less is blessed of the better. 8And here men that die receive tithes; but there he receiveth them, of whom it is 9And as I may so say, Levi also, who receiveth tithes, payed tithes in Abraham. 10For he was yet in the loins of his father, when Melchisedec met him. 11If therefore perfection were by the Levitical priesthood, (for under it the people received the law,) what further need was there that another priest should rise after the order of Melchisedec, and not be called after the order of Aaron? 12For the priesthood being changed, there is made of necessity a change also of the law. 13For he of whom these things are spoken pertaineth to another tribe, of which no man gave attendance at the altar. 14For it is evident that our Lord sprang out of Juda; of which tribe Moses spake nothing concerning priesthood. 15And it is yet far more evident: for that after the similitude of Melchisedec there ariseth another priest, 16Who is made, not after the law of a carnal commandment, but after the power of an endless life. 17For he testifieth, Thou art a priest for ever after the order of Melchisedec.
Verse 14 … For it is evident that our Lord sprang out of Juda; of which tribe Moses spake nothing concerning priesthood.
The priesthood was formed in Aaron who was a Levite.
Exodus 4:14a And the anger of the LORD was kindled against Moses, and he said, Is not Aaron the Levite thy brother?….
God's purposes are fulfilled according to His will rather than human merit or tradition.
Genesis 49:1-2 1And Jacob called unto his sons, and said, Gather yourselves together, that I may tell you thatwhich shall befall you in the last days. 2Gather yourselves together, and hear, ye sons of Jacob; and hearken unto Israel your father.
At the end of Jacob's life he gathered his sons together to share what will befall them in the last days. In other words Jacob prophesizes the future of his sons and their lineage.
From verse 3ff he speaks. In verse 22 he comes to Joseph.
Genesis 49:22-26 22Joseph is a fruitful bough, even a fruitful bough by a well; whose branches run over the wall: 23The archers have sorely grieved him, and shot at him, and hated him: 24But his bow abode in strength, and the arms of his hands were made strong by the hands of the mighty God of Jacob; (from thence is the shepherd, the stone of Israel:) 25Even by the God of thy father, who shall help thee; and by the Almighty, who shall bless thee with blessings of heaven above, blessings of the deep that lieth under, blessings of the breasts, and of the womb: 26The blessings of thy father have prevailed above the blessings of my progenitors unto the utmost bound of the everlasting hills: they shall be on the head of Joseph, and on the crown of the head of him that was separate from his brethren.
Although Ruben was the first born he forfeited his birth right and it fell to Joseph.
Jacob said that Joseph was a fruitful bough or fruitful vine.
This can be documented in the lives of his two sons Ephraim and Manasseh: Numbers 1:33-35, De 33:17…
Joshua 17:17 And Joshua spake unto the house of Joseph, even to Ephraim and to Manasseh, saying, Thou art a great people, and hast great power: thou shalt not have one lot only:
To be continued.