The Jews of Khaibar, fancying themselves safe from any attack of the Mussulmans, never let an opportunity escape to do them harm; and copying the manner in which Mohammad had proceeded against the Makkans, the Jews found out a good way to satisfy their rancour. The region between Khaibar and the sea was inhabited by the tribe of the Ghatafans, their allies, and they had come to an agreement to block the road and stop all Mussulman caravans leaving Al-Madinah to travel to Syria. The damage inflicted from these tactics had often made the Prophet think about sending an expedition against the Jews of Khaibar, but he was too busy round about Makkah, to carry out this plan.
On returning from Al-Hudaibiyah, the ten years' truce, signed with the Quraish, freed him from all anxiety as regarded them, and the Revelation he received at that moment: "He rewarded them with a speedy victory. * And with a rich booty," (The Qur'an, xlviii, 18-19), seeming to him to apply to Khaibar, and nothing else, he hesitated no longer, and decided to march against this fortress, the last stronghold of the Jews in Arabia.
The Ghatafans, secretly forewarned by Abdullah, the "Hypocrite," rushed to the aid of the Jews, their allies, but on arriving at the Wadi'r Raji, they found that the Mussulman forces had outstripped them and thus they were cut off from the road to Khaibar. Whilst brought to a dead stop, disagreeably surprised, they heard noises behind them, near their tents, and imagining that part of the Mussulman "qawm" had been diverted to take them in the rear, they turned back in great haste.
The palm-gardens of Khaibar, spreading between the sombre heights of the Harra like an emerald lake whence emerged rocky, citadel-crowned islets, came suddenly into view, after passing through a ravine. To be able to take possession of them, the Prophet invoked the aid of the Almighty. But night coming on, Mohammad postponed the attack till the following day. When the first rays of the sun gilded the tops of the date-trees, the Khaibar husbandmen left their strongholds to go in their gardens; their spades, pickaxes and baskets hanging from their shoulders. Suddenly, they found themselves confronted by the Believers' army debouching from the Harra; spearheads and swords reflecting the light of the rising sun in ensanguined radiance.
'Mohammad and his Jihsh!' they cried, and throwing away implements and baskets, fled as fast as their legs would carry them. 'Allah is great!' proclaimed the Prophet. 'Khaibar shall be destroyed. When we swoop down on the territory of a nation, its awakening is terrible! Lo and behold the sinister omen! On our behalf, its inhabitants abandon their tools that will serve to undermine their ramparts and dig their graves.'
The first of the many Khaibar citadels to fall into the Mussulmans' hands was that of Na'im. It was there they had to mourn the loss of Mahmud ibn Maslama, who, tired of having fought all day in the sun, wearing heavy armour, had imprudently gone close to the rampart to rest in the shade. A mill-stone, hurled from an embrasure, smashed the valiant soldier's helmet, split his skull, and caused the skin of his forehead to fall down over his eyes. In that parlous state, the wounded man was brought into the presence of the Prophet who put the strip of flesh back in its place, fastening a turban round it; but the best of attention was unavailing in face of such a serious injury, and it was not long before Mahmud gave up the ghost.
The citadels of Natha, the next to be invested, resisted more obstinately. In order to force the besieged to capitulate, the Prophet gave orders to cut down under their eyes four hundred palm-trees of their oasis, but all in vain. He therefore put an end to such devastation, contrary to his principles, for as he has said: 'Among all trees, there is one which is blessed like a Mussulman: 'tis the palm.'
The siege continuing, famine began to make itself felt, discouraging the besiegers, when Umar, having taken a Jew prisoner, the captive, to save his life, offered to give the Prophet valuable information. In the cellars of Sa'b ibn Mu'adh, one of the Natha citadels, called after the man, instruments of warfare of all kinds were stored: battering-rams; catapults for siege purposes; and armour, shields, pikes, lances and swords for the equipment of combatants. Just then, this fort happened to be weakly garrisoned, and the Jewish captive undertook to take the Mussulmans inside by means of a secret itinerary known to him alone.
Mohammad having accepted the offer, seized upon Sa'b easily, and thanks to the machines he found therein, which he used to destroy the ramparts, he captured the remaining fortresses of Natha, one after the other. They all contained provisions in abundance. While taking one of these forts, the poet Amr ibn u'l-Uhayha, pursuing one of the enemy, dealt him a furious sabre-cut, aiming at his legs to stop him in his flight. But the blade, too short, striking the empty air, rebounded from the force of the blow and pierced Amar's knee, setting up such strong hemorrhage that he expired soon afterwards, being sacrificed by his own hand, whilst fighting for Allah.
The most important of all the Khaibar citadels was still standing: that of Al-Qamus, in which Kinana, Prince of the Banu-Nadir, had taken refuge. It was defended by Marhab al-Yahudi, an illustrious warrior. Built on the top of a vertical black rock, with smooth sides, and surrounded by cleverly-designed fortifications, this fort was said to be impregnable. After ten days of desperate efforts against the ramparts, the Believers, however, succeeded in effecting a breach, into which leapt the Prophet, setting the example to his companions; but after having been in the greatest danger, he was compelled to retrace his steps.