“Not so, my father!” Joseph said. “This one is the firstborn; put your right hand on his head.”
Here is, I. The blessing with which Jacob blessed the two sons of Joseph, which is the more remarkable because the apostle makes such particular mention of it (Heb 11:21), while he says nothing of the blessing which Jacob pronounced on the rest of his sons, though that also was done in faith. Observe here, 1. Jacob was blind for age, Gen 48:10.
Commenting on Genesis 48:8-22
And Joseph said unto his father, not so, my father,.... It is not right, it should not so be, that the right hand should be put on the youngest, and the left hand on the eldest: for this is the firstborn; directing him to Manasseh, and seeking to guide his hand towards him: put thy right hand upon his head; Joseph was for proceeding according...
Joseph said - Not so, my father - Joseph supposed that his father had made a mistake in laying his right hand on the head of the youngest, because the right hand was considered as the most noble, and the instrument of conveying the highest dignities, and thus it has ever been considered among all nations, though the reason of it is not particularly obvious.