Haamek Davar on Genesis
And grasp him with your hand: She would not need to carry him much at all, but he would rather walk with his feet; but you should still grasp him with your hand. And included in [this phrase] is that he would be strengthened from her until she would be strengthened from him. And He further stated about this, for a great nation, etc..
Radak on Genesis
קומי...והחזיקי את ידך, do not let your hand go of him, (do not abandon him) for he will not die by thirst, for I will still make him into a great nation.