"upon your hand": This is the left hand. You say this, but perhaps it is the right? Though there is no proof for this, it is intimated in (Isaiah 48:3) "My hand has also founded on earth, and My right hand has spanned the heavens," and (Judges 5:26) "Her hand reached for the tent pin, her right for the workmen's hammer," indicating that "hand," unqualified, is the left hand.