| Matthew Henry's Concise Commentary 42:7-20 Joseph was hard upon his brethren, not from a spirit of revenge, but to bring them to repentance. Not seeing his brother Benjamin, he suspected that they had made away with him, and he gave them occasion to speak of their father and brother. 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. Joseph settled at last, that one of them should be left, and the rest go home and fetch Benjamin. It was a very encouraging word he said to them, I fear God; as if he had said, You may be assured I will do you no wrong; I dare not, for I know there is one higher than I. With those that fear God, we may expect fair dealing.
Pulpit CommentaryVerse 17. - And he put them all together into ward (literally, and he assembled them into prison) three days. Ostensibly in consequence of their unwillingness to agree to his proposal, but in reality to give them an experience of the suffering which they had inflicted on him, their brother, and so to awaken in their hearts a feeling of repentance. Yet the clemency of Joseph appears in this, that whereas he had lain three long years in prison as the result of their inhumanity towards him, he only inflicts on them a confinement of three days.
Gill's Exposition of the Entire BibleAnd he put them all together into ward three days. In order to consult together, and agree who should be sent to fetch their brother; and which it seems probable in this length of time they could not agree upon, no one caring to be the bringer of such evil tidings to their father.
Jamieson-Fausset-Brown Bible Commentary17-24. put them … into ward three days—Their confinement had been designed to bring them to salutary reflection. And this object was attained, for they looked upon the retributive justice of God as now pursuing them in that foreign land. The drift of their conversation is one of the most striking instances on record of the power of conscience [Ge 42:21, 22].
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