Ephraim and Manasseh are now about twenty years old so that, as Luther notes, it is strange to read of them being brought out from between Joseph’s knees as if they were little children, but this could equally be translated ‘from by his knees’. Joseph has evidently been waiting for this moment and wants his father to bless the boys individually, so he brings them out from where they have been waiting by him.
Jacob is a man of God through and through. When a man like Jacob keeps the promises in view, God reveals more and more to that person. Do you want to understand more and more? Then deal conscientiously with the light you already have. Obey commands, reflect on promises.