Genesis 42:15

“Hereby ye shall be proved, etc.] Whether spies, or not, namely, by producing their youngest brother, said to be at home with his father: by the life of Pharaoh ye shall not go forth hence, except your youngest brother come hither: the phrase, “by the life of Pharaoh”, seems to be the form of an oath, as it was common with many nations, especially with the Scythians, who used to swear by the royal throne f1749, and the Romans, in later times, by the life, health, and genius of their emperor; and this custom of swearing by the life of their king, or by his head, continued with the Egyptians, as Aben Ezra says, unto his times; though some take this to be a wish or prayer for the life of…”

“By the life of Pharaoh--It is a very common practice in Western Asia to swear by the life of the king. Joseph spoke in the style of an Egyptian and perhaps did not think there was any evil in it. But we are taught to regard all such expressions in the light of an oath (Mat 5:34; Jam 5:12).”

“- Joseph and Ten of His Brethren 1. שׁבר sheber, “fragment, crumb, hence, grain.” בר bar “pure,” “winnowed,” hence, “corn” (grain). 6. שׁליט shallı̂yṭ, “ruler, governor, hence,” Sultan. Not elsewhere found in the Pentateuch. 25. כלי kelı̂y, “vessel,” here any portable article in which grain may be conveyed. שׂק śaq, “sack,” the very word which remains in our language to this day. אמתחת 'amtachath “bag.” Twenty years, the period of Joseph’s long and anxious waiting, have come to an end. The dreams of his boyhood are now at length to be fulfilled. The famine has reached the chosen family, and they look at one another perplexed and irresolute, not knowing what to do. Genesis 42:1-5 The aged…”

“42:15-17 Joseph put the brothers in jail for three days to see if they had a conscience functioning about what they had done (42:21-23). The brothers had similarly thrown Joseph into a cistern-prison while they decided what to do with him (37:24).”