Tafsir of Al-Mutaffifeen 83:14

Kalla (Nay) is a deterrent to the sinful aggressor against that false statement, and a refutation of him regarding it. His saying—Exalted and Majestic is He—Bal rana 'ala qulubihim ma kanu yaksibun (Nay, but that which they used to earn has covered their hearts) is an explanation of what led them to utter such a monstrous claim. That is: there is nothing in Our verses that warrants such a false statement to be made about them. Rather, what they persisted in acquiring of disbelief and acts of disobedience has mounted their hearts and dominated them, until it became like rust upon a mirror, standing between them and the recognition of the Truth; thus, they said what they said.

Al-Rayn originally means rust. It is said, "The sin has rusted (rana) upon him," and "It has veiled him (ghana)," using both rayn and ghayn. It is also said that sleep "rusted" (rana) in a person, meaning it settled deeply within him. The root of al-rayn is dominance; it is said that wine has "rusted" (ranat) over the mind of the drinker, meaning it dominated it, and that faintness has "rusted" (rana) over the mind of the sick person, meaning it overwhelmed it. Abu Zayd said: It is said of a man that he is "rusted" (rina bihi) when he falls into something from which he cannot escape. What is intended by it here is the love of sins that has become deep-seated, by way of the analogy that it is like the rust that blackens a mirror or silver, changing it from its original state.

Imam Ahmad, al-Tirmidhi, al-Hakim (who authenticated it), al-Nasa'i, Ibn Majah, Ibn Hibban, and others narrated from Abu Hurayrah, from the Prophet—may Allah bless him and grant him peace—that he said: "When a servant commits a sin, a black spot is dotted on his heart. If he repents, desists, and seeks forgiveness, his heart is polished. But if he returns, it increases until it covers his heart. That is the rayn which Allah the Exalted mentioned in the Quran: 'Nay, but that which they used to earn has covered their hearts.'"

Ibn al-Mundhir and others narrated from Mujahid that he said: They used to consider al-rayn to be al-tab' (the seal). They mentioned causes for it. In a hadith narrated by 'Abd ibn Humayd via the path of Khulayd ibn al-Hakam from Abu al-Mujayr, he said that the Prophet—peace be upon him—said: "Four traits are corruptive to the hearts: interacting with the foolish, for if you interact with him, you become like him, while if you remain silent regarding him, you are safe from him; the abundance of sins, which corrupt the hearts, and Allah the Exalted has said: 'Nay, but that which they used to earn has covered their hearts'; seclusion with women, taking pleasure in them, and acting according to their opinions; and sitting with the 'dead.' It was asked, 'O Messenger of Allah, who are they?' He replied, 'Every wealthy person whom his wealth has made insolent.'"

It has been read with the assimilation (idgham) of the lam into the ra. Abu Ja'far ibn al-Badhish said: The reciters have reached a consensus on the assimilation of the lam into the ra, except for what comes from the pause of Hafs upon bal—a light and brief pause to indicate the izhar (manifestation). It is not as he claimed regarding the consensus; for in al-Lawami', from Qalun by all his paths, is the manifestation of the lam before the ra, such as in the saying of the Exalted: bal rafa'ahu Allahu ilayh and bal rabbukum. In the book of Ibn 'Atiyyah, it is stated: "And Nafi' read bal rana without assimilation." It also states therein: "And he also read it with assimilation and imalah (inclination)."

Sibawayh said regarding the lam with the ra, such as in ashghal rahimahu: "Manifestation and assimilation are both good." He also said: "If it [the lam] is not the lam of the definite article—such as the lam of hal and bal—then assimilation is better. If it is not assimilated, it is a dialect of the people of the Hijaz, and it is valid Arabic." In al-Kashshaf, it is stated: "It was read with the assimilation of the lam into the ra, and with manifestation, and the assimilation is better." The alif has been inclined (imalah) and thickened (tafkhim), so let this be observed.