Arcana Coelestia # 6292
6292. 'Place your right hand on his head' means that good should accordingly occupy the first place. This is clear from the meaning of 'placing the right hand on a head' as considering to occupy the first place, as above in 6269, 6287. The placing of his hand by one on the head of another when he was going to bless belonged to a custom received from the ancients. For the head is where a person's actual powers of understanding and will reside, whereas the body is where actions in response and in obedience to them are located. Thus 'placing a hand on the head' was a representative act, denoting that a blessing should be imparted to a person's understanding and will, thus to his real self. That same custom originating in those ancient times remains even to this day and is followed at ordinations as well as in blessings.
Genesis 48:17-20
17
And when Joseph saw that his father laid his right hand upon the head of Ephraim, it displeased him: and he held up his father's hand, to remove it from Ephraim's head unto Manasseh's head.
18
And Joseph said unto his father, Not so, my father: for this is the firstborn; put thy right hand upon his head.
19
And his father refused, and said, I know it, my son, I know it: he also shall become a people, and he also shall be great: but truly his younger brother shall be greater than he, and his seed shall become a multitude of nations.
20
And he blessed them that day, saying, In thee shall Israel bless, saying, God make thee as Ephraim and as Manasseh: and he set Ephraim before Manasseh.
