Tafsir of Yusuf 12:63

"So when they returned to their father, they said, 'O our father! The measure has been withheld from us'"—meaning: [the king] ruled that it shall be withheld after this day if we do not go with our brother Benjamin, as the king said to us: "If you do not bring him to me, there shall be no measure for you from me." Expressing this in such a way is a metaphor; the reason for adopting it is that no previous prohibition had occurred. In this is evidence that granting privileges time after time was customary between them and him—peace be upon him. It is said: the verb is used in its literal sense, and the intent is the withholding of an additional load for their absent brother, so his camel was returned empty, based on the narration that he—peace be upon him—did not give him a load.

"So send with us our brother [Benjamin] to Egypt"—this indicates that the cause of the prohibition was his absence from them.

"We shall obtain our measure"—meaning: of the food we need. This is the response to the request. It is said: the original construction is "remove the obstacle and we shall obtain the measure," so the response is "remove," but it was omitted and replaced by "we shall obtain the measure" because since the withholding of the measure was tied to their not bringing their brother, sending him would remove that obstacle. It was replaced with this because it is the intended [result]. It is also said that the second of the two parts was used to indicate the sequence for the first as a form of hyperbole. The root of this verb is naktayil (على وزن نفعيل), where the ya was changed to an alif because it was vocalized and preceded by a fatha, then it was dropped due to the meeting of two vowelless letters. It is strange that al-Sajawandi reported that al-Mazini asked Ibn al-Sikkit in the presence of al-Wathiq about the pattern of naktal, and he replied: tafa'al. Al-Mazini then said: "Then its past tense would be katala," thus refuting him in the most eloquent manner.

Hamza and al-Kisa’i read it as yaktal (with a ya of the third person), attributing it to the brother metaphorically because he is the cause of the obtaining of the measure, or [it means] "our brother shall obtain the measure," so his obtaining is added to our obtaining. Abu Hayyan strengthened, through this reading, the opinion that the prohibition remains in its literal sense.

"And indeed, we will be his guardians"—so that no harm befalls him. This is closing the door to any excuse, and they were hyperbolic in that, as is not hidden. In some reports—though its status is not hidden—it is said that when they entered upon their father—peace be upon him—they greeted him with a weak greeting. He said to them: "O my sons, why do you greet me with a weak greeting, and why do I not hear the voice of Simeon among you?" They replied: "O our father, we came to you from the side of the greatest of people in kingship, and we have never seen the like of him in knowledge, wisdom, humility, tranquility, and dignity. If he has any resemblance, he resembles you. But we are a household created for trials; he accused us and claimed he would not believe us until you send Benjamin with us with a message from you informing him of your sorrow, what has caused your sorrow, the quickening of your gray hair, and the loss of your sight. He has withheld the measure from us for the future if we do not bring him our brother. So send him with us, we shall obtain our measure, and indeed we will be his guardians until we bring him to you."