Genesis 49 (kjv)1And Jacob called unto his sons, and said, Gather yourselves together, that I may tell you that which shall befall you in the last days.
2Gather yourselves together, and hear, ye sons of Jacob; and hearken unto Israel your father.
3Reuben, thou art my firstborn, my might, and the beginning of my strength, the excellency of dignity, and the excellency of power:
4Unstable as water, thou shalt not excel; because thou wentest up to thy father's bed; then defiledst thou it: he went up to my couch.
[NOTE: Jacob didn't ~disown his son here, nor state anywhere that Reuben wouldn't become one of the future 'twelve' tribes of Israel. All he really did, was simply state the facts of the matter concerning his eldest son. The rabbinical, Ashkenazi/Japhethan, Asian/Hybrid, Indo-European, Aryan, crypto-Muslim, crypto-Pagan, Canaanite, false, fraudulent, Nazi/Zionist ~'Jews' have tried (and often succeeded) to convince Christians and the world that Ephraim and Manassah took Reuben and Simeon's place as one of the 'twelve'. But the constant shuffling of different tribes into the prophetic equation that is "Israel" (the ~real "chosen" People of God, made in His image -- not "Judah") has been entirely political and based in ~greed.
(After all, it states in scriptures literally scores of times, that the love of money is the "root of all evil". The only other sin which is admonished in scriptures as often as greed, is "fornication".)...
... Because, had Reuben's lack of morals been the issue, then all the sinning sons of Jacob would have also been permanently replaced by grandsons, or perhaps with otherwise adopted children. But that wasn't Jacob's intent; his blessings (or curses, as the cases may have been with some of them) went to ~all of his true, blood-related sons.
Had it been an issue of morals, then Simeon, Levi, and other sons which he spoke of in very ~neutral, noncommittal terms (ie Judah, Gad, Asher, Benjamin) might have also been removed from the list by their father, Jacob. But he did not do so.
And Joseph, his youngest son, was his pride and joy: so I don't believe that Jacob's blessings on Ephraim and Manassah were in any way meant to construe that Joseph would be left off his list of descendants. I think what it could mean more is that, of all Joseph's progeny, first Ephraim then Manassah were to be ~counted; his other sons would probably/possibly not be counted among the tribes of Israel.
In fact, by blessing those two sons exclusively, Jacob effectively ~excluded Joseph's other sons. Or did he? Hmm, interesting question. Why else would he (as much as he loved Joseph above all his other sons) single out Ephraim and Manassah? He was even determined to set Ephraim (the youngest of the two boys) over Manassah, in tribal status.
Nevertheless, in Revelations Joseph and Manassah are listed among the 'twelve', but Ephraim and Dan are omitted from that particular scripture. So, either the scribes had a Field Day with it, or it means something prophetically which we haven't figured out yet. I'm inclined to favor the second explanation in this case, but not in all other textual places where Jacob's sons' names have been substituted on lists of the tribes of Israel.
At different places in the scriptures (which were originally copied by hand, by ~scribes), Reuben (the first born son), Joseph (the youngest and most beloved son of Jacob), Levi (the father of Israel's priestly tribe), and Ephraim (the son of Joseph whom Jacob ~favored above his older brother, Manassah)... were all left off the 'list'. Why? I believe that it was for politics and greed.
Historically, in Patriarchal societies, the eldest sons or in any case the most favored children of the fathers, were often (like Joseph) the target of violent jealousies and undermining conspiracies hatched by other family members (sometimes including or even intigated by wives/mothers). They were sometimes badmouthed by their siblings who were of lesser familial or tribal status. Some were murdered, or otherwise gotten out of the way (as Joseph was sold into Egyptian slavery, and his brothers all conspired together to lie to their father about the circumstances of his disappearance from the family).
So there has always been in Patriarchal societies practicing primogeniture inheritance, much rivalry over the inheritance of lands, money, property, etc. That fact explains the strange scriptural confusion over the actual, true tribes of Israel.
And it isn't ~necessary that there be exactly twelve of them, total (assuming Jacob wished to include Ephraim and Manassah, there were/are probably 14). Which would fit the Revelations scripture, wherein 144,000 witnesses are chosen from the elect, out of just 12 tribes. Because, Dan and Ephraim are not listed there.
Why? Ephraim was very much beloved of Jacob; and of Dan, Jacob only said that he would "judge his people, as one of the tribes of Israel" and that he would cause the 'horse and rider' to fall backwards unexpectedly, as "an adder in the path, that biteth the horse heels". (Perhaps you've heard the old proverb or 'saying': "He will come down, off his high horse"). So I don't believe it's due to God's disapproval of Dan or of Ephraim, but must be for some other reason. Is it because Dan and Ephraim are perhaps the 'two witnesses' who will judge Israel? Perhaps, but we'll know for sure someday.]
5Simeon and Levi are brethren; instruments of cruelty are in their habitations.
6O my soul, come not thou into their secret; unto their assembly, mine honour, be not thou united: for in their anger they slew a man, and in their selfwill they digged down a wall.
7Cursed be their anger, for it was fierce; and their wrath, for it was cruel: I will divide them in Jacob, and scatter them in Israel.
8Judah, thou art he whom thy brethren shall praise: thy hand shall be in the neck of thine enemies; thy father's children shall bow down before thee.
9Judah is a lion's whelp: from the prey, my son, thou art gone up: he stooped down, he couched as a lion, and as an old lion; who shall rouse him up?
10The sceptre shall not depart from Judah, nor a lawgiver from between his feet, until Shiloh come; and unto him shall the gathering of the people be.
11Binding his foal unto the vine, and his ass's colt unto the choice vine; he washed his garments in wine, and his clothes in the blood of grapes:
12His eyes shall be red with wine, and his teeth white with milk.
13Zebulun shall dwell at the haven of the sea; and he shall be for an haven of ships; and his border shall be unto Zidon.
14Issachar is a strong ass couching down between two burdens:
15And he saw that rest was good, and the land that it was pleasant; and bowed his shoulder to bear, and became a servant unto tribute.
16Dan shall judge his people, as one of the tribes of Israel.
17Dan shall be a serpent by the way, an adder in the path, that biteth the horse heels, so that his rider shall fall backward.
18I have waited for thy salvation, O LORD.
19Gad, a troop shall overcome him: but he shall overcome at the last.
20Out of Asher his bread shall be fat, and he shall yield royal dainties.
21Naphtali is a hind let loose: he giveth goodly words.
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.
27Benjamin shall ravin as a wolf: in the morning he shall devour the prey, and at night he shall divide the spoil.
28All these are the twelve tribes of Israel: and this is it that their father spake unto them, and blessed them; every one according to his blessing he blessed them.
[NOTE: I don't think it can be stated any more clearly than that.]
29And he charged them, and said unto them, I am to be gathered unto my people: bury me with my fathers in the cave that is in the field of Ephron the Hittite,
30In the cave that is in the field of Machpelah, which is before Mamre, in the land of Canaan, which Abraham bought with the field of Ephron the Hittite for a possession of a buryingplace.
31There they buried Abraham and Sarah his wife; there they buried Isaac and Rebekah his wife; and there I buried Leah.
32The purchase of the field and of the cave that is therein was from the children of Heth.
33And when Jacob had made an end of commanding his sons, he gathered up his feet into the bed, and yielded up the ghost, and was gathered unto his people.