Genesis 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; they should not form a third tribe, but should be included in those of Ephraim and Manasseh, though their names were entered in the genealogical tables, Numbers 26:28; 1 Chronicles 7:14, Through this adoption of his oldest sons on the part of Jacob, Joseph was given the right of the firstborn in his inheritance, 1 Chronicles 5:2. By this disposition of the inheritance Jacob incidentally honored Rachel.