9 And Joseph remembered the dreams which he dreamed of them, and said unto them, Ye are spies; to see the nakedness of the land ye are come. 10 And they said unto him, Nay, my lord, but to buy food are thy servants come. 11 We are all one man’s sons; we are true men, thy servants are no spies. 12 And he said unto them, Nay, but to see the nakedness of the land ye are come. 13 And they said, Thy servants are twelve brethren, the sons of one man in the land of Canaan; and, behold, the youngest is this day with our father, and one is not.
It seems a sudden and strange accusation to call this group of men traitors. Obviously, Joseph knows that his brothers have a sneaky and destructive streak, not only because of how they treated him, but because of their tricking and slaughtering the men in the city of Shalem. But it seems doubtful to me that he genuinely expects his brothers to be here for anything other than buying the grain as they have claimed. More likely it seems to me that he was casting around for a reason to keep them engaged with him for a while longer. To what end, perhaps even he does not yet know, only that he will keep them in play until he can decide what to do with them.
The response of Joseph’s brothers, doubling down on their heritage makes me wonder if they felt the appearance of ten men together was what Joseph had found suspicious. Did they think he saw this was an excessive emissary to buy grain, and so they needed to explain why so many of them were here together?
Unfortunately we don’t have any explicit insights into either party’s inner thoughts in this exchange. Regardless, in the brothers’ haste to explain themselves, they let slip some crucial information that Joseph will be able to use in his charade. One of their brothers is absent, and one of their brothers “is not.” Now he can turn the focus of the conversation to the matter of missing brothers and prove where their hearts are on the matter.