Manasseh was the elder son and Joseph brought him to Jacob’s right hand that he might receive the superior blessing but Jacob crossed his arms so that his right hand was on Ephraim’s head. When Joseph noticed this change he objected but Jacob insisted that the blessing go to the younger son. This is a recurring feature of the bestowal of God’s blessing - going, not to the elder son entitled to it by fleshly descent, but to the younger. This is to repudiate the flesh and to emphasise that the blessings of God are bestowed according to his will.
Ephraim means “fruitful”, being called this because when he was born Joseph acknowledged that God had made him fruitful in the land of Egypt, Genesis 41:52Waiting for response for Genesis 41:52 and Ephraim would be blessed above his brother. The descendants of these two sons of Joseph would obtain a double portion in the promised land. And so it transpired: Joseph became, not just one tribe in Israel, but two, Ephraim and Manasseh, both of whom developed large populations and occupied extensive lands, thus fulfilling the word of God.
In those days fathers blessed their sons before dying, and this is especially significant in the case of these men of God because, guided by God’s spirit, they expressed the outworking of the LORD’s purpose. Hebrews 11:20-21Waiting for response for Hebrews 11:20-21