Genesis 44:5

“[Is] not this [it], in which my lord drinketh, etc.] Which was for his own particular use, and so the more ungrateful in them to take it, and whereby indeed he divineth? according to our version and others, Joseph is here represented by his steward as a diviner or soothsayer, and so he might be thought to be by the Egyptians, from being such an exact interpreter of dreams, foretelling things to come, and that he made his divinations by the silver cup; and we are told that the Assyrians, Chaldeans, and Egyptians, used to fill basins with water, in which they put plates of silver and precious stones, marked with certain characters, and pronouncing certain words, called to the devil, who…”

“Is 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.”

“- The Ten Brothers Were Tested Joseph has had the satisfaction of seeing his brother Benjamin safe and well. He has heard his brothers acknowledging their guilt concerning himself. He resolves to put their attachment to Benjamin, and the genuineness of their change of disposition, to a test that will at the same time expose Benjamin to no hazard. Genesis 44:1-5 And my cup. - Besides returning each man’s money as before, a silver cup of Joseph’s is put in Benjamin’s bag, after which, when daylight comes, they are dismissed. They are scarcely out of the town when Joseph’s steward is ordered to overtake them, and charge them with stealing the cup. “And whereby indeed he divineth.” Divining by…”

“44:5 This description would make the brothers understand that the ruler knew things that others could not. • Hydromancy (pouring water into oil) and oenomancy (pouring wine into other liquids) were methods of divination used in the ancient Near East that would have required such a cup. Joseph was continuing his ruse (see 42:7; cp. 30:27; see also Lev 19:26; Num 23:23; Deut 18:10-11)—he knew that only God grants revelation (see Gen 37:5-9; 40:8; 41:16).”