By way of his servant, here Joseph had just accused his bothers of theft of a common item of luxury which he represents to them as that by which he has power to divine. But, these brothers all sincerely deny having committed such a thing, by saying they are not covertly adverse to Egypt.
For the want of food, and in face of an accusation of being adverse to one's own good, all men will claim that they are good and are all one man’s sons. And, they really are all one man’s sons: Adam’s. But, this verse is the most powerful way in which Joseph is a figure of Christ, because Christ was not a son of Adam and so could judge all Adam's sons.
But, the story surrounding this verse has the men pleading innocence, and as consenting to the guilt of the one among them of whom shall be found the object of guilt. Yet, as 'counter-conspired' by Joseph, that one is not guilty at all, but all of them except that one: to steal a mere drinking vessel from a 'house of a luxury of such vessels' was nothing to the theft of the very life of one who had never known either any luxury nor any way to defend against being murdered.