Gen 49:1 And Jacob called unto his sons, and said, Gather yourselves together, that I may tell you that which shall befall you in the last days.

This of course means their descendants that would come after them. Even though we do not know where the tribes of Israel are today, rest assured God knows where they are at. We don't have to search and pretend that the tribes are the Indians, the British or some other group of people in order to make sure we will be saved in the end. Our salvation depends upon our faith in Jesus Christ alone, not if we are descendants of some tribe of Israel. We don't have to worry about the 144 thousand or other such numbers if we already belong to Jesus Christ. Those 144, 000 are those who are saved in the last days from the tribes of Israel. Israel as a nation does not accept Jesus as the Messiah. That will change. There will be much more than 144 thousand saved but those are the first ones to be saved from Israel and are the ones who will be the latter day preachers. I speculate that this occurs after the believing church will have been taken out or raptured. Jesus is coming for people who are without spot or wrinkle washed in the blood of Jesus. He is not coming for half baked, people who claim to be saved and are still living in open unconfessed sin. If we are lukewarm and sleeping spiritually when the Lord comes, we will be left behind I don't care what we claimed to have years ago. Read the letters to the churches in Revelation for references and also the words of Jesus in:

Luk 21:34 And take heed to yourselves, lest at any time your hearts be overcharged with surfeiting, and drunkenness, and cares of this life, and so that day come upon you unawares.
Luk 21:35 For as a snare shall it come on all them that dwell on the face of the whole earth.
Luk 21:36 Watch ye therefore, and pray always, that ye may be accounted worthy to escape all these things that shall come to pass, and to stand before the Son of man.

Anyway back to Jacob:

Gen 49:2 Gather yourselves together, and hear, ye sons of Jacob; and hearken unto Israel your father.
Gen 49:3 Reuben, thou art my firstborn, my might, and the beginning of my strength, the excellency of dignity, and the excellency of power:
Gen 49:4 Unstable 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.

Even though Reuben most probably repented of this sin, it caused a blight upon his descendents. The tribe of Reuben did not excel like the tribe of Judah. Our actions affect our children and sometimes pass to our descendents.

Gen 49:5 Simeon and Levi are brethren; instruments of cruelty are in their habitations.
Gen 49:6 O my soul, come not thou into their secret; unto their assembly, mine honor, be not thou united: for in their anger they slew a man, and in their self-will they digged down a wall.
Gen 49:7 Cursed 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.

Even though the tribe of Levi was chosen for the priesthood, they were scattered throughout the tribes.  Jacob is very severe in telling them that their cruelty in the case of Shechem was very evil. It might have been the beginning of Israel having a bad name among nations around them.

Gen 49:8 Judah, 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.
Gen 49:9 Judah 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?
Gen 49:10 The scepter 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.
Gen 49:11 Binding 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:
Gen 49:12 His eyes shall be red with wine, and his teeth white with milk.

Judah is the tribe from where we have the Jewish people. They are the ones who was to rule in Israel. They had kings until sin was found in them and the kingdom was temporarily taken from them until the coming of the king of kings, Jesus Christ who will rule the whole earth. Even so come Lord Jesus. Our Lord came from the tribe of Judah making Him a legal heir to the throne of David. Even though Joseph (husband of Miriam) was not the real father of Jesus, He was counted in the lineage. Mary (Miriam) was from the tribe of Judah also.

Gen 49:13 Zebulun shall dwell at the haven of the sea; and he shall be for a haven of ships; and his border shall be unto Zidon.
Gen 49:14 Issachar is a strong ass couching down between two burdens:
Gen 49:15 And 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.
Gen 49:16 Dan shall judge his people, as one of the tribes of Israel.
Gen 49:17 Dan shall be a serpent by the way, an adder in the path, that biteth the horse heels, so that his rider shall fall backward.
Gen 49:18 I have waited for thy salvation, O LORD.
Gen 49:19 Gad, a troop shall overcome him: but he shall overcome at the last.
Gen 49:20 Out of Asher his bread shall be fat, and he shall yield royal dainties.
Gen 49:21 Naphtali is a hind let loose: he giveth goodly words.
Gen 49:22 Joseph is a fruitful bough, even a fruitful bough by a well; whose branches run over the wall:
Gen 49:23 The archers have sorely grieved him, and shot at him, and hated him:
Gen 49:24 But 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:)
Gen 49:25 Even 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:
Gen 49:26 The 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.
Gen 49:27 Benjamin shall ravin as a wolf: in the morning he shall devour the prey, and at night he shall divide the spoil.
Gen 49:28 All these are the twelve tribes of Israel: and this is it that their father spoke unto them, and blessed them; every one according to his blessing he blessed them.

These tribes will be restored their rightful place in the latter days. 10 of the tribes lost their place because of idolatry and sin. Judah followed later but found their homeland again in 1948. God knows where every one of the tribes are scattered. They all will return home again.

Gen 49:29 And 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,
Gen 49:30 In 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 burial place.
Gen 49:31 There they buried Abraham and Sarah his wife; there they buried Isaac and Rebekah his wife; and there I buried Leah.

Jacob recognized that his place was with his first wife. He wanted to be buried where Abraham, Isaac and Leah were buried. This showed faith in the plans and purposes of God. I believe God's perfect will is that we marry once and stay with our first wife (husband).   God hates divorce and I believe sincerely that He does not approve of plural marriages.   He warned in the law of Moses for kings not to multiply wives to themselves.  I believe Jacob knew this in the end and only buried one wife, his first wife with Abraham, Isaac and their wives.  The other wives of these men were not buried there. 

Gen 49:32 The purchase of the field and of the cave that is therein was from the children of Heth.
Gen 49:33 And 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.

This describes what happens at death. The spirit (ghost) leaves the body and the body is dead. The spirit does not die but goes to await the latter day judgment. Before Jesus Christ came and died for sins, the righteous dead went to a place that was called Abraham's bosom. After Jesus died He went to that place and took those souls with Him to heaven. Now when a person who believes in Christ dies, His soul goes immediately to be with the Lord.

To be absent from the body is to be present with the Lord. The unrighteous go to Hell but it is a place where they do not have to go because Jesus made the way of escape if they would only repent of sin and believe the gospel.

Genesis 50