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.