Tafsir of Al-Baqarah 2:278

{O you who have believed} in appearance, {fear Allah}—that is, protect yourselves from His punishment— {and leave}—that is, abandon— {what remains of interest} that you have owed to you by people, {if you are believers} from the core of the heart, for the proof of that is the compliance with what you have been commanded.

The conditional clause's response is omitted, relying on what preceded it. The "min" (in "what remains of") is partitive, related to an omitted state (hal) from the subject of "remains." It is also said it relates to "remains." Al-Hasan recited "baqa" by changing the ya to an alif, according to the dialect of the Tayy tribe.

As-Suddi stated that this verse was revealed concerning al-Abbas ibn Abd al-Muttalib (may Allah be pleased with him) and a man from the Banu al-Mughirah, who were partners during the Pre-Islamic period (Jahiliyyah), lending money at interest to people from Thaqif, specifically the Banu 'Amrah (the Banu 'Amr ibn 'Umayr). Islam arrived while they possessed great wealth from interest, so they abandoned it when this was revealed.

Ibn Abi Hatim recorded from Muqatil that he said: This verse was revealed concerning the Banu 'Amr ibn 'Umayr ibn 'Awf al-Thaqafi, and Mas'ud ibn 'Amr ibn 'Abd Yalil ibn 'Amr, and Rabi'ah ibn 'Amr, and Habib ibn 'Umayr—they were all brothers. They were the creditors, and the debtors were the Banu al-Mughirah of the Banu Makhzum. They had been lending to the Banu al-Mughirah at interest during the Jahiliyyah. When the Prophet (may Allah's peace and blessings be upon him) made a peace treaty with Thaqif, they demanded their interest from the Banu al-Mughirah, and it was a great sum of wealth. The Banu al-Mughirah said, "By Allah, we will not pay interest in Islam, as Allah the Exalted and His Messenger have abolished it for the Muslims."

Mu'adh ibn Jabal (or it is said, 'Attab ibn Asid) became aware of their situation and wrote to the Messenger of Allah (may Allah's peace and blessings be upon him) stating that the Banu 'Amr ibn 'Umayr were demanding their interest from the Banu al-Mughirah. Then Allah the Exalted revealed: {O you who have believed}, etc. The Messenger of Allah (may Allah's peace and blessings be upon him) wrote to Mu'adh ibn Jabal: "Present this verse to them. If they comply, then they may have their capital; if they refuse, then declare war against them from Allah the Exalted and His Messenger." This is the meaning of His saying: [next verse].