Gen. 48:1 And 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. 

Gen. 48:2 And one told Jacob, and said, Behold, thy son Joseph cometh unto thee: and Israel strengthened himself, and sat upon the bed. 

Gen. 48:3 And Jacob said unto Joseph, God Almighty appeared unto me at Luz in the land of Canaan, and blessed me, 

Gen. 48:4 And 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. 

Gen. 48:5 And 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. 

Gen. 48:6 And thy issue, which thou begettest after them, shall be thine, and shall be called after the name of their brethren in their inheritance. 

Sometime later Joseph was told that his father was failing, so he took his sons with him to see Jacob.  When Jacob heard that Joseph had come, he summoned the strength to sit up in his bed.  He told Joseph about “God Almighty” appearing to him and promising to bless him and increase his numbers and give the land of Canaan to his descendants “for an everlasting possession.”  I think the name he used for God was to emphasize to Joseph that he was confident that God Almighty would bring this promise to pass.  He told him that his sons, Ephraim and Manasseh, would be counted as equal with his own sons—just like Reuben and Simeon—when the time came to make tribal allotments of the land.  This basically amounted to giving Joseph the double portion that was part of the birthright that Reuben forfeited.  There is no record in scripture of Joseph having any more sons.

Fruchtenbaum: “First Chronicles 5:1-2 points out that while Judah had the preeminence, Joseph had the birthright; and with this adoption, the two sons of Joseph became the legal sons of Jacob.”

1 Chronicles 5:1–2 “Now 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. For Judah prevailed above his brethren, and of him came the chief ruler; but the birthright was Joseph’s:)….”

Gen. 48:7 And as for me, when I came from Padan, Rachel died by me in the land of Canaan in the way, when yet there was but a little way to come unto Ephrath: and I buried her there in the way of Ephrath; the same is Bethlehem.

Gen. 48:8 And Israel beheld Joseph’s sons, and said, Who are these? 

Gen. 48:9 And Joseph said unto his father, They are my sons, whom God hath given me in this place. And he said, Bring them, I pray thee, unto me, and I will bless them. 

Gen. 48:10 Now the eyes of Israel were dim for age, so that he could not see. And he brought them near unto him; and he kissed them, and embraced them. 

Gen. 48:11 And Israel said unto Joseph, I had not thought to see thy face: and, lo, God hath shewed me also thy seed. 

Gen. 48:12 And Joseph brought them out from between his knees, and he bowed himself with his face to the earth. 

Gen. 48:13 And Joseph took them both, Ephraim in his right hand toward Israel’s left hand, and Manasseh in his left hand toward Israel’s right hand, and brought them near unto him. 

Gen. 48:14 And Israel stretched out his right hand, and laid it upon Ephraim’s head, who was the younger, and his left hand upon Manasseh’s head, guiding his hands wittingly; for Manasseh was the firstborn. 

The way the verses are worded, it’s like listening to an old man’s wandering mind.  All of a sudden he remembered the death of Rachel and having to bury her along the road to Ephrath (Bethlehem).  Then he saw Joseph’s sons but didn’t recognize them.  (I remember visiting my great-grandmother in her last years.  Sometimes she would know me and my mom, and sometimes she wouldn’t and thought we were someone else.)  When Joseph told him that they were his sons, Jacob wanted them brought closer so he could bless them.  He immediately kissed and hugged them.  Israel’s eyes were really bad, and he could barely see. Jacob expressed his joy at being allowed not only to see Joseph again, but also Joseph’s children.  These kids were 17+ years old.  Joseph bowed before his father and placed his sons before Jacob so that his right hand was on Manasseh (the oldest) and his left hand was on Ephraim.  But Israel crossed his arms and “wittingly” (he knew what he was doing) put his right hand on Ephraim and his left on Manasseh. 

Gen. 48:15 And he blessed Joseph, and said, God, before whom my fathers Abraham and Isaac did walk, the God which fed me all my life long unto this day, 

Gen. 48:16 The Angel which redeemed me from all evil, bless the lads; and let my name be named on them, and the name of my fathers Abraham and Isaac; and let them grow into a multitude in the midst of the earth. 

Gen. 48:17 And when Joseph saw that his father laid his right hand upon the head of Ephraim, it displeased him: and he held up his father’s hand, to remove it from Ephraim’s head unto Manasseh’s head. 

Gen. 48:18 And Joseph said unto his father, Not so, my father: for this is the firstborn; put thy right hand upon his head. 

Gen. 48:19 And his father refused, and said, I know it, my son, I know it: he also shall become a people, and he also shall be great: but truly his younger brother shall be greater than he, and his seed shall become a multitude of nations. 

Gen. 48:20 And he blessed them that day, saying, In thee shall Israel bless, saying, God make thee as Ephraim and as Manasseh: and he set Ephraim before Manasseh. 

Gen. 48:21 And Israel said unto Joseph, Behold, I die: but God shall be with you, and bring you again unto the land of your fathers. 

Gen. 48:22 Moreover I have given to thee one portion above thy brethren, which I took out of the hand of the Amorite with my sword and with my bow. 

Jacob then proceeded to bless Joseph.  He acknowledged the God of his fathers as his shepherd and the Angel of his deliverance from all harm.  He asked that God bless these boys who were to be called by his name (as his sons) and make them increase greatly on the earth.  When Joseph realized what Jacob had done with his hands, he tried to correct him to have his right hand on Manasseh.  His father, however, refused to cooperate—he knew what he was doing.  He declared that both become great nations—but Ephraim, the younger, would become the greatest.  Then Israel told Joseph that he (Israel) would soon die, but that God would take them all back to the land of their fathers.  Then he reiterated that he was giving Joseph an extra portion of land they were to inherit, since he was now the father of two tribes.  

The right hand is indicative of strength and authority in scripture.  Jesus is now sitting at the right hand of God the Father.

Exodus 15:6 “Thy right hand, O LORD, is become glorious in power: thy right hand, O LORD, hath dashed in pieces the enemy.”

Psalm 20:6 “Now know I that the LORD saveth his anointed; he will hear him from his holy heaven with the saving strength of his right hand.”

Psalm 118:16 “The right hand of the LORD is exalted: the right hand of the LORD doeth valiantly.”

Isaiah 41:10 “Fear thou not; for I am with thee: be not dismayed; for I am thy God: I will strengthen thee; yea, I will help thee; yea, I will uphold thee with the right hand of my righteousness.”

Hebrews 12:2 “Looking unto Jesus the author and finisher of our faith; who for the joy that was set before him endured the cross, despising the shame, and is set down at the right hand of the throne of God.”

“which I took out of the hand of the Amorite with my sword” – This sounds like Jacob had conquered the land of the Amorites.  I don’t remember reading about this.

Constable: “The word for "portion" means ridge or shoulder (of land) and is the same as "Shechem." Shechem lay in Manasseh"s tribal territory. The Israelites later distributed the land among the tribes (Joshua 24:1) and buried Joseph at Shechem (Joshua 24:32)….Jacob spoke as though he had taken Shechem from the Amorites by force (Genesis 48:22). Probably Jacob viewed Simeon and Levi"s slaughter of the Shechemites as his own taking of the city ( Genesis 34:27-29). [Note: Waltke, Genesis , p601.] Another view is that Moses used the perfect tense in Hebrew, translated past tense in English ("took"), prophetically. In this usage, which is common in the Old Testament, the writer spoke of the future as past. The idea was that, since God predicted them by divine inspiration, events yet future are so certain of fulfillment that one could speak of them as already past. Here the thought is that Israel (Jacob) would take Canaan from the Amorites, the most powerful of the Canaanite tribes, not personally, but through his posterity (cf. Genesis 15:16). [Note: Keil and Delitzsch, 1:385.]”