A Commentary, Critical, Practical, and Explanatory on the Old and New Testaments, by Robert Jamieson, A.R. Fausset and David Brown  at sacred-texts.com
gen 44:1POLICY TO STAY HIS BRETHREN. (Gen. 44:1-34)
And Joseph commanded the steward--The design of putting the cup into the sack of Benjamin was obviously to bring that young man into a situation of difficulty or danger, in order thereby to discover how far the brotherly feelings of the rest would be roused to sympathize with his distress and stimulate their exertions in procuring his deliverance. But for what purpose was the money restored? It was done, in the first instance, from kindly feelings to his father; but another and further design seems to have been the prevention of any injurious impressions as to the character of Benjamin. The discovery of the cup in his possession, if there had been nothing else to judge by, might have fastened a painful suspicion of guilt on the youngest brother; but the sight of the money in each man's sack would lead all to the same conclusion, that Benjamin was just as innocent as themselves, although the additional circumstance of the cup being found in his sack would bring him into greater trouble and danger.
gen 44:2put my cup, the silver cup, in the sack's mouth--It was a large goblet, as the original denotes, highly valued by its owner, on account of its costly material or its elegant finish and which had probably graced his table at the sumptuous entertainment of the previous day.
gen 44:3As soon as the morning was light, the men were sent away--They commenced their homeward journey at early dawn (see on Gen 18:2); and it may be readily supposed in high spirits, after so happy an issue from all their troubles and anxieties.
gen 44:4When they were gone out of the city . . . Joseph said unto his steward--They were brought to a sudden halt by the stunning intelligence that an article of rare value was missing from the governor's house. It was a silver cup; so strong suspicions were entertained against them that a special messenger was despatched to search them.
gen 44:5Is not this it in which my lord drinketh--not only kept for the governor's personal use, but whereby he divines. Divination by cups, to ascertain the course of futurity, was one of the prevalent superstitions of ancient Egypt, as it is of Eastern countries still. It is not likely that Joseph, a pious believer in the true God, would have addicted himself to this superstitious practice. But he might have availed himself of that popular notion to carry out the successful execution of his stratagem for the last decisive trial of his brethren.
gen 44:6he overtook them, and he spake . . . these words--The steward's words must have come upon them like a thunderbolt, and one of their most predominant feelings must have been the humiliating and galling sense of being made so often objects of suspicion. Protesting their innocence, they invited a search. The challenge was accepted [Gen 44:10-11]. Beginning with the eldest, every sack was examined, and the cup being found in Benjamin's [Gen 44:12], they all returned in an indescribable agony of mind to the house of the governor [Gen 44:13], throwing themselves at his feet [Gen 44:14], with the remarkable confession, "God hath found out the iniquity of thy servants" [Gen 44:16].
gen 44:16Judah said, What shall we say?--This address needs no comment--consisting at first of short, broken sentences, as if, under the overwhelming force of the speaker's emotions, his utterance were choked, it becomes more free and copious by the effort of speaking, as he proceeds. Every word finds its way to the heart; and it may well be imagined that Benjamin, who stood there speechless like a victim about to be laid on the altar, when he heard the magnanimous offer of Judah to submit to slavery for his ransom, would be bound by a lifelong gratitude to his generous brother, a tie that seems to have become hereditary in his tribe. Joseph's behavior must not be viewed from any single point, or in separate parts, but as a whole--a well-thought, deep-laid, closely connected plan; and though some features of it do certainly exhibit an appearance of harshness, yet the pervading principle of his conduct was real, genuine, brotherly kindness. Read in this light, the narrative of the proceedings describes the continuous, though secret, pursuit of one end; and Joseph exhibits, in his management of the scheme, a very high order of intellect, a warm and susceptible heart, united to a judgment that exerted a complete control over his feelings--a happy invention in devising means towards the attainment of his ends and an inflexible adherence to the course, however painful, which prudence required.