Tafsir of Fussilat 41:34

(And not equal are the good deed and the bad deed): An initial clause brought forth to clarify the virtues of actions performed between people, following the clarification of the virtues of actions performed between the servant and the Lord, Exalted and Majestic is He. This is to encourage the Messenger of Allah (peace be upon him) to be patient with the harm of the polytheists and to respond to their evil with good. The ruling is general; meaning, the good trait and the bad trait are not equal in their effects and consequences. The second "la" (nor/and not) is an augmentation to emphasize the negation, similar to His (the Exalted’s) saying: "nor the shade, nor the heat," because the verb istawa (to be equal) cannot be satisfied with a single subject.

(Repel with that which is better): An initiation clarifying the good outcome of the good deed. It means: repel the evil wherever you encounter it from some of your enemies with that which is better than it, which is the good deed. This is on the basis that "the better" refers to that which is absolutely superior, or the best possible good deed with which it can be repelled—such as showing kindness to one who has done evil, for that is better than mere pardoning. Thus, ahsan (better) is used in its apparent sense, and that which is being compared against is generic, hence it is omitted, as in "Allah is greater" (Allahu akbar). Its presentation in the form of an answer to a questioner who asks, "How should I act?" is for the sake of hyperbole and to indicate that it is an important matter that warrants attention and inquiry. It is also for hyperbole that ahsan (better) is placed in the position of al-hasanah (the good deed), for he who repels with the best will find it easy to repel with that which is lesser.

From what we have mentioned, it is known that the "good deed" and the "bad deed" are not intended to be two specific things. It is narrated from Ali (may Allah ennoble his countenance) that the good deed is the love of the Messenger and his family (peace be upon them), and the bad deed is hatred for them. From Ibn Abbas, it is narrated that the good deed is La ilaha illa Allah (There is no god but Allah) and the bad deed is polytheism (shirk). Al-Kalbi said: They are the two calls toward them. Al-Dahhak said: Gentleness and obscenity. Others said: Patience. Others said: Courteousness and harshness. Others said otherwise. It is not hidden that some of these narrations can hardly be intended here; perhaps they were not authentically proven from those to whom they were attributed.

It is possible that the intent is to state the variation of good and bad deeds within themselves, meaning that good deeds vary between "good" and "better," and bad deeds do the same. In this case, the definite article in "the good deed" and "the bad deed" denotes the genus, the second "la" is not an augmentation, and the superlative (af’al) is in its literal sense. The discourse in "repel" and what follows would then be based on the meaning of a connective "fa" (so), implying: since each of the two categories varies in its individuals, then repel the bad or the worst with the better of the two good deeds. The omission of the "fa" is for the exception we mentioned, which is the stronger of the two ways of joining; perhaps the first (interpretation) is closer.

(Then behold, the one between whom and you there is enmity will be as though he were a devoted friend)

A clarification of the result of the commanded repulsion. When you do that, your hostile enemy becomes like a compassionate friend. Ibn Atiyyah said: "As though" (ka'anna) was used to imply analogy because an enemy does not truly become a devoted friend merely by repelling evil with that which is better; rather, his outward appearance improves, so he is likened to a devoted friend. Perhaps this is a case of sufficiency with the minimum necessary; this is viewed in terms of the general case, otherwise, enmity may indeed cease entirely through this, as it is said: "Verily, enmity turns into affection by remedying lapses with good deeds."

"The one between whom and you there is enmity" is more eloquent than saying "your enemy," which is why it was chosen over it, despite its brevity. It is said that this verse was revealed regarding Abu Sufyan ibn Harb, who was an avowed enemy of the Messenger of Allah (may Allah grant him peace and blessings), and he became, according to the Sunnis, a sincere ally. It seems that what he possessed was transferred to his son’s son, Yazid, upon him is what he deserves from Allah, the Exalted and Majestic.