We may well wonder that Joseph, during the twenty years that he had now been in Egypt, especially during the last seven years that he had been in power there, never sent to his father to acquaint him with his circumstances; nay, it is strange that he who so often went throughout all the land of Egypt (Gen 41:45, Gen 41:46) never made an excursion to Canaan, to visit his aged father, when he was in the borders of Egypt, that lay next to Canaan. Perhaps it would not have been above three or four days' journey for him in his chariot. It is a probable conjecture that his whole management of himself in this affair was by special direction from Heaven, that the purpose of God concerning Jacob and his family might be accomplished. When Joseph's brethren came, he knew them by many a satisfactory token, but they knew not him, little thinking to find him there, Gen 42:8. He remembered the dreams (Gen 42:9), but they had forgotten them. The laying up of God's oracles in our hearts will be of excellent use to us in all our conduct. Joseph had an eye to his dreams, which he knew to be divine, in his carriage towards his brethren, and aimed at the accomplishment of them and the bringing of his brethren to repentance for their former sins; and both these points were gained.
I. He showed himself very rigorous and harsh with them. The very manner of his speaking, considering the post he was in, was enough to frighten them; for he spoke roughly to them, Gen 42:7. He charged them with bad designs against the government (Gen 42:9), treated them as dangerous persons, saying, You are spies, and protesting by the life of Pharaoh that they were so, Gen 42:16. Some make this an oath, others make it no more than a vehement asseveration, like that, as thy soul liveth; however it was more than yea, yea, and nay, nay, and therefore came of evil. Note, Bad words are soon learned by converse with those that use them, but not so soon unlearned. Joseph, by being much at court, got the courtier's oath, By the life of Pharaoh, perhaps designing hereby to confirm his brethren in their belief that he was an Egyptian, and not an Israelite. They knew this was not the language of a son of Abraham. When Peter would prove himself no disciple of Christ, he cursed and swore. Now why was Joseph thus hard upon his brethren? We may be sure it was not from a spirit of revenge, that he might now trample upon those who had formerly trampled upon him; he was not a man of that temper. But, 1. It was to enrich his own dreams, and complete the accomplishment of them. 2. It was to bring them to repentance. 3. It was to get out of them an account of the state of their family, which he longed to know: they would have discovered him if he had asked as a friend, therefore he asks as a judge. Not seeing his brother Benjamin with them, perhaps he began to suspect that they had made away with him too, and therefore gives them occasion to speak of their father and brother. Note, God in his providence sometimes seems harsh with those he loves, and speaks roughly to those for whom yet he has great mercy in store.
II. They, hereupon, were very submissive. They spoke to him with all the respect imaginable: Nay, my lord (Gen 42:10) - a great change since they said, Behold, this dreamer comes. They very modestly deny the charge: We are no spies. They tell him their business, that they came to buy food, a justifiable errand, and the same that many strangers came to Egypt upon at this time. They undertake to give a particular account of themselves and their family (Gen 42:13), and this was what they wanted.
III. He clapped them all up in prison for three days, Gen 42:17. Thus God deals with the souls he designs for special comfort and honour; he first humbles them, and terrifies them, and brings them under a spirit of bondage, and then binds up their wounds by the Spirit of adoption.
IV. He concluded with them, at last, that one of them should be left as a hostage, and the rest should go home and fetch Benjamin. It was a very encouraging word he said to them (Gen 42:18): I fear God; as if he had said, "You may assure yourselves I will do you no wrong; I dare not, for I know that, high as I am, there is one higher than I." Note, With those that fear God we have reason to expect fair dealing. The fear of God will be a check upon those that are in power, to restrain them from abusing their power to oppression and tyranny. Those that have no one else to stand in awe of ought to stand in awe of their own consciences. See Neh 5:15, So did not I, because of the fear of God.

One is not - An elliptical sentence, One is not alive.

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 ye 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 ye 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.

Ye are spies--This is a suspicion entertained regarding strangers in all Eastern countries down to the present day. Joseph, however, who was well aware that his brethren were not spies, has been charged with cruel dissimulation, with a deliberate violation of what he knew to be the truth, in imputing to them such a character. But it must be remembered that he was sustaining the part of a ruler; and, in fact, acting on the very principle sanctioned by many of the sacred writers, and our Lord Himself, who spoke parables (fictitious stories) to promote a good end.