(He said, "O son of my mother...")
The mother is specifically mentioned by attribution to elicit sympathy and soften his heart, not—as has been claimed—because he was his maternal half-brother; for the majority hold that they were full brothers. Hamza and al-Kisa’i read it as ya bna ummi with a kasra on the mim.
"...do not seize [me by] my beard, nor my head." That is, by the hair of my head, for "seizing" is more appropriately applied to it. Some have claimed that his words "by my beard" also imply the hair of the beard, for the term "beard" originally denotes the limb upon which the hair grows, and the act of seizing does not fit the limb itself very well. You know, however, that the common usage of "beard" refers to the hair growing on that specific limb. The apparent meaning of the verses and reports is that he (peace be upon him) seized them literally. It is narrated that he seized the hair of his head with his right hand and his beard with his left. He (peace be upon him) was stern, uncompromising, and wrathful for the sake of Allah the Almighty. He had witnessed what he had witnessed, and he concluded that Aaron (peace be upon him) had fallen short in a way that warranted discipline—even if it did not remove him from the sphere of infallibility established for the Prophets (peace be upon them). Thus, he did what he did, and he performed it personally; there is no impropriety in this whatsoever, nor is it contrary to the Sacred Law. Therefore, the objection imagined by the Imam—that anger either removes one’s reason or it does not, and that the former is not believed by any Muslim, while the latter does not resolve the question of why there would be a lack of infallibility—is refuted, and he answered it with that which carries no weight.
Isa ibn Sulayman al-Hijazi read bi-lihyati with a fatha on the lam, which is the dialect of the people of the Hijaz.
"I feared..." to the end. This is a resumption [of speech] to provide the reason for the prohibition, by confirming that he had not disobeyed his command nor failed in serving the interest. That is: I feared that if I had fought some of them with others, they would have annihilated and dispersed each other; or I feared that if I had joined you with those who believed, you would say, "You have caused division among the Children of Israel," through your own opinion, despite them being sons of one man—as is indicated by their being mentioned with this title rather than "the people." The consequence of fighting causing division is evident, and likewise the consequence of joining Moses (peace be upon him) with those who believed—as this might lead to fighting. It has been said that he (peace be upon him) meant by "division," according to the first interpretation, the kind of division accompanied by fighting from which no future unity can be hoped.
"...and you did not observe..." meaning, you did not regard.
"...my word." The sentence is coordinated with "you have caused division," meaning: I feared that you would say the totality of the two sentences and attribute to me the division of the Children of Israel and the failure to observe your word to me and your commandment to me. It is also permissible that the sentence is in the position of a state (hal) from the pronoun in "you have caused division," meaning: I feared you would say, "You have caused division among them without observing my word"—that is, I feared you would say the totality of this statement. By "my word" [attributed to the first person], he intended his words (peace be upon him): "Take my place among my people and do right..." and so on. The essence of his excuse (peace be upon him) is: I saw that the right course was to preserve the common folk, to appease them, and to rebuke them in a way that would not disrupt the order of their harmony and unity, and would not be a cause for you to blame me until you returned to them, at which point you would be the one to rectify the matter as you see fit. Especially since the people had weakened me and were on the verge of killing me, as he explained in another verse.
Ibn al-Mundhir recorded from Ibn Jurayj that which indicates that what is meant by the "word" attributed [to the first person] is the word of Aaron (peace be upon him), and the sentence "you did not observe" is in the position of a state (hal) from the pronoun in "you would say." That is: I feared you would say that without waiting for my word and the explanation of the true state of affairs. So, reflect upon this. Abu Ja'far read "and you did not observe" (wa-lam tarqubi) with a damma on the ta and a kasra on the qaf, as an imperfect tense verb arqabu.