Tafsir of Al-A'raf 7:138

(And We brought the Children of Israel across the sea) — This marks the commencement, after the conclusion of the story of Pharaoh, of the story of the Children of Israel and an explanation of the innovations they introduced after Allah, the Exalted, had bestowed upon them what He bestowed and shown them the signs He had shown them. This serves as a consolation for the Messenger of Allah (may Allah bless him and grant him peace) regarding what he witnessed from the Jews in Medina, for they conducted themselves with him according to the habit of their ancestors with his brother, Moses (peace be upon him). It also serves as a warning to the believers not to neglect taking account of themselves and observing the blessings of Allah, the Exalted, upon them; for the Children of Israel fell into what they fell into because of their heedlessness of what Allah, the Exalted, had favored them with.

Jāwaznā (We brought across) means jāznā (we crossed/caused to cross). It is also read as jawwaznā (with the tashdid), which also carries the meaning of crossing; it is made transitive by the ba (in bi-bani Isra’il), meaning: We caused the sea to be crossed with them. The intended sea is the Sea of Qulzum. In Majma’ al-Bayan, it is stated that it was the Nile of Egypt, but as stated in al-Bahr, this is an error. It is narrated from al-Kalbi that Moses (peace be upon him) led them across on the day of Ashura after the destruction of Pharaoh and his people, so they fasted it in gratitude to Allah, the Exalted.

(So they came upon) — meaning they passed by, after the crossing, (a people) — Qatadah said: They were from Lakhm, the name of a tribe [attributed as Ibn Abd al-Barr authenticated to Lakhm ibn ‘Adi ibn ‘Amr ibn Saba]. It is also said: They were of the Canaanite Amalekites whom Moses (peace be upon him) was commanded to fight.

((who were devoted to idols of theirs)) — meaning they were persistent in worshiping them and adhered to them. As Ibn al-Mundhir and others narrated from Ibn Jurayj, they were statues of cows made of copper, and this was the origin of the matter of the Calf. Others said: They were made of stone, and others said: They were actual cows. Hamzah and al-Kisa’i read (ya’kifun) with a kasra on the kaf.

(They said) — when they observed that, (O Moses, make for us a god) — an example that we may worship, (as they have gods). The kaf (in ka-ma) is attached to an omitted element that functions as an adjective for "a god." Ma is a relative pronoun, lahum (for them) is its connector, and alihah (gods) is an appositive (badal) to the pronoun hidden within it. The estimate is: "Make for us a god, existing as one like that which is established for them."

Abu al-Baqa’ allowed that ma could be an obstruction (kaffah) for the kaf—and thus a nominal sentence followed it—or that it could be an infinitive (masdariyyah), and lahum is attached to a verb, i.e., "just as gods have been established for them."

(He said, "Indeed, you are a people who are ignorant.")

He (peace be upon him) expressed amazement at their statement after they had witnessed the Great Sign and the Supreme Evidence. He described them as ignorant in the most complete manner, for he did not mention a direct object for "you are ignorant," treating the verb as though it were intransitive, or because omitting the object indicates its universality—meaning: You are ignorant of everything, and thus ignorance of Lordship is included a fortiori. He emphasized this with inna (indeed), and by inserting the word "people" (qawm) and making what was intended to be the news (the predicate) a description of it. Thus, as the Allamah said, it becomes as something realized and known. This, as al-Shihab mentioned, is a subtle point in a predicate that serves as a premise for a claim—that the predicate, due to the clarity of its matter and the existence of evidence for it, is as if it were a realized, known fact, thereby increasing its emphasis and confirmation. Were it not for this, there would be no rhetorical benefit in inserting the qualified noun.