Charles Ellicott Commentary Genesis 42:11

"We are all one man`s sons; we are true men, thy servants are no spies." — Genesis 42:11 (ASV)

We are all one man’s sons. —Joseph’s brothers had probably expected this accusation, and their answer, as Abravanel points out, is a sound one: for no man would send his whole family on so dangerous an errand. And thus they emphasize their family relations as a proof of their being true, that is, honest, just men, with no evil designs; and Joseph, who was glad in this way to obtain information about his father and Benjamin, finally, after persisting in the accusation until he had learned all he wished to know, accepts their argument as valid.