He placed his brethren according to their seniority, as if he could certainly divine. Some think they placed themselves so according to their custom; but if so, I see not why such particular notice is taken of it, especially as a thing they marvelled at.
Related Commentaries of Genesis 43:33
Genesis 43:33
33 And they sat before him, the firstborn according to his birthright, and the youngest according to his youth: and the men marvelled one at another.