(84–86) “And when We took your covenant: ‘Do not shed one another’s blood or drive one another from your homes.’ Then you acknowledged it, and you yourselves bear witness. * Yet here you are, killing one another and driving a group of your own people from their homes, supporting one another against them in sin and aggression. If they come to you as captives, you ransom them, although driving them out was forbidden to you. Do you then believe in part of the Scripture and disbelieve in part? What can be the recompense of those among you who do this except disgrace in the life of this world? And on the Day of Resurrection they will be consigned to the severest punishment. Allah is not unaware of what you do. * Those are the ones who have purchased the life of this world at the price of the Hereafter. Their punishment will not be lightened, nor will they be helped.”
The conduct mentioned in this verse was that of those who lived in Medina at the time of the revelation. Before the Prophet, peace and blessings be upon him, was sent, al-Aws and al-Khazraj—who were the Ansār—were polytheists and fought one another according to the customs of the pre-Islamic age of ignorance. The three Jewish tribes—Banū Qurayza, Banū al-Nadīr, and Banū Qaynuqā—had settled among them, and each Jewish tribe entered into an alliance with one of the factions of Medina.
Thus, whenever they fought, a Jew would aid his ally against the latter’s opponents, whom the other Jewish faction aided (1). A Jew would therefore kill another Jew and drive him from his home whenever expulsion and plunder occurred. Then, when the war had ended and captives had been taken by both sides, the Jews would ransom one another.
All three matters had been made obligatory for them: they were forbidden to shed one another’s blood or drive one another from their homes, and if they found one of their people captive, they were required to ransom him. They observed the last command but abandoned the first two. Allah therefore denounced them for this, saying: “Do you then believe in part of the Scripture”—namely, the command to ransom captives—“and disbelieve in part?”—namely, the prohibitions against killing and expulsion.
This provides the clearest proof that faith entails fulfilling commands and avoiding prohibitions, and that commanded deeds are part of faith. Allah Most High says: “What can be the recompense of those among you who do this except disgrace in the life of this world?” This indeed befell them: Allah disgraced them and gave His Messenger power over them, so that some were killed, some were taken captive, and others were banished.
“And on the Day of Resurrection they will be consigned to the severest punishment,” meaning the greatest punishment. “Allah is not unaware of what you do.”
Allah Most High then explains what caused them to disbelieve in part of the Scripture while believing in another part: “Those are the ones who have purchased the life of this world at the price of the Hereafter.” They imagined that failing to aid their allies would bring them disgrace, so they chose the Fire over disgrace. He therefore says: “Their punishment will not be lightened.” Rather, it will remain unabated in its severity, and they will never experience any respite. “Nor will they be helped,” meaning that no affliction will be warded off from them.