12:70
Atlength when he had furnished them forth with provisions (suitable) for them, he put the drinking cup into his brother’s saddle-bag. Then shouted out a
crier: “O ye (in) the caravan! Behold! ye are thieves, without doubt!”
According to the commentary Anwār al-Bayān, Prophet Yūsuf (Joseph) devised a plan that would allow his younger brother Benjamin to remain with him in Egypt. After arranging provisions for his brothers, Joseph instructed that a royal drinking cup—used for measuring grain during distribution—be placed secretly in Benjamin’s luggage. This action was part of a deliberate strategy to create circumstances under which Benjamin could be lawfully detained.
When Joseph’s attendants later discovered that the measuring cup was missing, they were confused and unaware that Joseph himself had orchestrated the situation. An announcement was then made to the departing caravan accusing them of theft. The brothers, surprised by the accusation, asked what item had been lost. The officials responded that the king’s measuring cup was missing and offered a reward of a camel-load of grain for whoever recovered it, with the announcer personally guaranteeing the reward.
The brothers strongly denied the accusation, asserting that they had not come to cause corruption in the land and had no history of theft. In response, Joseph’s attendants asked what the appropriate punishment should be if the stolen item were found among their belongings. The brothers replied that, according to the legal custom they followed, the person in whose possession the stolen item was discovered would himself become the penalty—meaning that the individual would be detained and treated as a slave. They explained that this was the form of punishment applied to those who committed acts of wrongdoing within their legal tradition.
Reference:
Madani, Muhammad. Anwar ul Bayan. (vol. 3 p. 77-78).