What does Genesis 48:5 mean?
Joseph has brought his two oldest sons to his dying father's bedside to be blessed (Genesis 48:1–4). After reminding Joseph of God's promise to give to his descendants the land of Canaan as an "everlasting possession," Jacob now turns to blessing Joseph's sons.As it happens, this is a tremendous blessing, indeed! In essence, Jacob formally adopts Ephraim and Manasseh as his own two sons. No longer will they be considered simply grandsons. Instead, they will be given the same generational privileges as Jacob's other sons. More than that: Jacob appears to elevate Joseph's two sons to the rank of his firstborn sons above even Reuben and Simeon.
The effect of Jacob's action is that Joseph and his family will now receive the birthright and a double portion of the family inheritance. Why would Jacob do this? As the following chapter will reveal, Jacob has not forgotten the sins of his oldest sons Reuben (Genesis 49:3–4) and Simeon (Genesis 49:5–7). But it's more than that. Jacob has remained faithful to the end in his devotion to his beloved late wife Rachel and the two sons that she bore to him (Genesis 48:7).