John Gill Commentary Genesis 42:16

"Send one of you, and let him fetch your brother, and ye shall be bound, that your words may be proved, whether there be truth in you: or else by the life of Pharaoh surely ye are spies." — Genesis 42:16 (ASV)

Send one of you, and let him fetch your brother He proposes that one of them might be sent by them to their father's house, and bring, Benjamin down to Egypt: and you shall be kept in prison; the rest of them till he came: that your words may be proved, whether [there be any] truth in you; by this it would be seen whether they were men of truth and honesty or not; and should their brother be brought they would appear to be good men and true: or else, by the life of Pharaoh, surely you [are] spies; should not their brother they spoke of be produced, it would be a plain case that they were not the honest men they pretended to be, nor did they come merely to buy corn, but had an ill intention.