Sforno on Genesis 39:1/ספורנו על בראשית ל״ט:א׳

1ויוסף הורד, whereas Joseph was brought to Egypt against his will, Yehudah, at the same time exiled himself. During that period all the things related earlier had befallen Yehudah. During that period Joseph had been brought to Egypt by the Ishmaelites, the owners of the camels who were also agents acting on behalf of others.