Tafsir of Al-Baqarah 2:279

"But if you do not," meaning: if you do not do what you have been commanded regarding piety and abandoning the remaining interest, whether while denying its prohibition or while acknowledging it.

"Then be informed," meaning: be certain. This is how al-Hasan read it, and it is the interpretation narrated from Ibn Abbas (may Allah be pleased with them both).

"Of a war from Allah and His Messenger." This is like the war against the apostates in the first case [denying its prohibition], and like the war against the rebels in the second case [acknowledging it]. It has been said: It is not a literal war, but rather a threat and intimidation. However, the majority of exegetes maintain the first interpretation. Hamzah and ‘Asim, in the narration of ibn ‘Ayyash, read fa-adhinu (with a long vowel), meaning: "Make known/announce," whether to yourselves, to one another, or to others. This necessarily implies their knowledge of the war in the most complete manner. The indefinite nature of "war" (harb) is for the purpose of magnification; hence, it was not linked to Allah through genitive construction (idafa). Abu Ya'la narrated from Ibn Abbas that when this was revealed, Thaqif said: "We have no power to wage war against Allah and His Messenger (may Allah bless him and grant him peace)."

"But if you repent," from that which necessitates war, "you shall have your principal sums," you may take them and nothing else. "Do not wrong," your debtors by taking the excess, "and you shall not be wronged," by others through the reduction of the principal or by means of procrastination. Al-Mufaddal narrated from ‘Asim the reading: la tuzlamuna (passive voice) for the first and la tazlimuna (active voice) for the second, the reverse of the first reading. The sentence is either an independent statement—which is the apparent meaning—or it is in the position of a state (hal) referring to the pronoun in "for you" (lakum), where the governing agent is the implication of existence in the prepositional phrase, as it acts as a predicate. This is the opinion of al-Akhfash.

The necessity of suspending this ruling upon their repentance implies it is not established if they do not repent. If the lack of repentance occurs while denying the prohibition, they are apostates. According to Imam Abu Hanifah (may Allah be pleased with him), their earnings during their apostasy become spoils (fay’) for the Muslims. Likewise, according to al-Shafi’i (may Allah be pleased with him), this applies to their remaining wealth, whereas according to us [the Hanafi school], it belongs to their heirs, and they [the apostates] possess nothing in any case.

If it occurs while acknowledging [the prohibition], then if they have power/might, they are on the verge of being killed; their heads are hardly secure, let alone their capital. Otherwise, the same applies according to Ibn Abbas; Ibn Jarir narrated from him that he said: "Whoever persists in usury and does not desist, it is the duty of the Imam of the Muslims to demand his repentance. If he desists, [it is well], otherwise, he is to be beheaded." A similar view is narrated from al-Sadiq (may Allah be pleased with him). As for others, they are to be imprisoned until their repentance becomes apparent, and they are not permitted to engage in any transactions at all. Thus, as long as they do not repent, no part of their wealth is surrendered to them; rather, it is only surrendered upon their death to their heirs.