Genesis 48:8

Who are these? - At Genesis 48:10 it is said, that Jacob's eyes were dim for age, that he could not see - could not discern any object unless it were near him; therefore, though he saw Ephraim and Manasseh, yet he could not distinguish them till they were brought nigh unto him.

He now observes and proceeds to bless the two sons of Joseph. "Who are these?" The sight and the observant faculties of the patriarch were now failing. "Bring them now unto me, and I will bless them." Jacob is seated on the couch, and the young men approach him. He kisses and folds his arms around them. The comforts of his old age come up before his mind. He had not expected to see Joseph again in the flesh, and now God had showed him his seed. After these expressions of parental fondness, Joseph drew them back from between his knees, that he might present them in the way that was distinctive of their age. He then bowed with his face to the earth, in reverential acknowledgment of the act of worship about to be performed. Joseph expected the blessing to be regulated by the age of his sons, and is therefore, careful to present them so that the right hand of his dim-sighted parent may, without any effort, rest on the head of his first-born. But the venerable patriarch, guided by the Spirit of him who doth according to his own will, designedly lays his right hand on the head of the younger, and thereby attributes to him the greater blessing.

The imposition of the hand is a primitive custom which here for the first time comes into notice. It is the natural mode of marking out the object of the benediction, signifying its conveyance to the individual, and implying that it is laid upon him as the destiny of his life. It may be done by either hand; but when each is laid on a different object, as in the present case, it may denote that the higher blessing is conveyed by the right hand. The laying on of both hands on one person may express the fulness of the blessing conveyed, or the fullness of the desire with which it is conveyed.