Genesis 44:5

Whereby indeed he divineth. The goblet was a valuable possession. It was not an ordinary drinking cup, but one, supposedly, capable of detecting any poisonous substance placed in it. Such cups were also used for the practice of magic. The word translated “divineth” means “to whisper,” “to mumble,” “to prophesy.” Classical writers speak of the Oriental practice of pouring water into a goblet and looking into it for representations of future events (Jamblichus De mysteriis iii. 14). Another custom described by the ancients consisted of pouring water into a goblet, dropping in pieces of gold and silver or precious stones, and then observing and interpreting the appearance in the water (Pliny Natural History xxxvii. 73; Strabo Geography xvi. 2. 39). That the steward was ordered to mention the practice of magic to the brothers does not imply that Joseph had actually adopted this superstitious practice himself. As previously (ch. 43:33), he was willing that they should believe he could read their thoughts. This would tend to unnerve them and lead them to abandon pretense.

On account of his great wisdom, the Egyptians probably attributed to Joseph the practice of magic. Had he not accurately predicted the years of plenty and of famine, and taken care that Egypt be prepared for the emergency? He certainly excelled their best “magicians” (ch. 41:8), and must therefore possess superior magic (see Ex. 8:19).

Perhaps his fame as a wise man had spread far and wide, even to foreign lands, so that the supposed thieves of the goblet might appropriately be asked whether they were unaware of this fact (Gen. 44:15).