Khaibar is situated about 100 miles to the north east of Medinah, and means, literally, a fortified place.  The Jews of Khaibar constituted a serious threat to the Muslims.  The Jews who had lost their fights against the Messenger of Allah (s.a.w.) had slowly and imperceptibly collected in the vicinity of this fort and had begun to incite their brethren to wage war against the Muslims. The valley surrounding Khaibar was considered as one of the most fertile of the desert oases and its great gardens of date palms were most jealously guarded by the various Jewish tribes whose territory it was.  The Jews of Khaibar were considered the bravest warriors, and they posed a most powerful challenge to the supremacy of Islam.
 The valley of Khaibar was studded with fortresses strongly situated on rocky hillocks, which numbered about ten.  Many of these strongholds were considered impregnable. The Jews, counting on their large numbers and upon their valor as well as their strongholds, resolved to resist.  When the Messenger of Allah (s.a.w.) heard of this he set out with 1,400 Muslims to face them.  The Jews, about 10,000 strong, all armored, collected themselves in their forts.  But, when besieged in any of their citadels, they could not resist very long and eventually evacuated it after one or two sorties.  The Muslims advanced fighting and subduing the forts until the last one appeared to be invulnerable.

 The Jews rallied around their chief, the king of their nation, Kinanah bin Al-Rab.  He lived in this strongly fortified citadel of Khaibar named Al-Qamus, built on a steep rock and considered totally unapproachable.  Three times the Muslim army returned unsuccessful from this fort.  Ultimately, the Messenger of Allah (s.a.w.) made his famous announcement which marks one of the most brilliant additions in the laurels of Imam Ali (a.s.).
 Realizing that the Muslim leaders present there were unable to subdue this last fort which occupied the key position for the Jews, the Messenger of Allah (s.a.w.), pointing to the banner of the Muslim army, announced:  "Tomorrow I shall hand over this banner to a man who attacks relentlessly and never flees away; he loves Allah and His Prophet and Allah and His Prophet love him, and he would not return until Allah grants him victory."
 This announcement kindled a desire in the heart of every Muslim present to be the man who was "beloved of God and His Prophet."  The most covetous for this unique honor was Sa’d bin Waqqas and Umar bin Khattab.  No one thought of Imam Ali (a.s.), the cousin and Vicegerent of the Holy Prophet (s.a.w).  The hero of all previous wars was suffering badly from sore eyes and could not see anything.

 Imam Ali (a.s.) who had been left behind in Medinah because of his illness, could not remain there and despite his loss of sight, left for Khaibar reaching there just on the eve of this great day.  The longed for the morning dawn, but the Messenger of Allah (s.a.w.) appeared not to take notice of anyone.  When he broke the silence he asked for Imam Ali (a.s.) and all, in one voice, answered that he was at a considerable distance and was suffering badly from sore eyes so that he was utterly unable to see.  The Prophet commanded them to bring Imam Ali (a.s.) to him.  On being informed of the Prophet’s (s.a.w.) call, Imam Ali (a.s.) presented himself to the Prophet (s.a.w) led by Selma bin Aku as he himself could not see his way.
 The Messenger of Allah (s.a.w.), taking Imam Ali (a.s.) head into his lap, applied the saliva of his mouth to his eyes and prayed for his recovery.  Instantaneously, his eyes became so clear as if he had never suffered from the disease.  It is said that throughout his life he never had anymore trouble with his eyes again.  The Messenger of Allah (s.a.w) handed over the banner to Imam Ali (a.s.), armed him with Dhulfiqar, and thus designated him as the man whom Allah and His Prophet loved.  He directed him to lead the assault and to fight until the Jews submitted.  Imam Ali (a.s.) with his force scrambled up the stony rock in front of the fortress and planted the banner over its top resolving never to recede until the citadel was taken.
 

The Jews sallied forth to drive down the assailants.  A Jewish priest asked Imam Ali (a.s.) his name which he gave as Ali bin Abi Talib or Haidar (the name his mother gave him).  The priest, hearing the name, warned his men that the assailant would not withdraw without capturing the citadel.  However, Harith, a Jewish champion, who had vigorously repulsed the previous attacks, stepped forward and killed several of the Muslims.  Imam Ali (a.s.) advanced and killed Harith in hand to hand combat.  The brother of Harith was a gigantic man with a huge form.  He was unequaled in valor among the Jews.  To revenge the death of his brother he came out covered from his neck to his waist with a double coat of mail wearing helmet for protection against the stroke of a scimitar.  He had a huge gird on both his sides and brandished a big spear with triple-forked sharp pointed heads.

 Stepping forwards from this Jewish lines he challenged his adversaries to single combat.
 "I am Marhab," he cried, "as all Khaibar knows, the greatest warrior in the world."  None among the Muslims would dare to go forward to confront him.  Imam Ali (a.s.) himself advanced wearing a scarlet vest covered with a breastplate of steel sighing:  "I am he whom his mother named Haidar, a lion of the wilderness; I weigh my foes in a gigantic balance."  Imam Ali’s words were not meaningless.  He knew, through inspiration, that Marhab had lately dreamt of a rugged lion tearing him to pieces; so he reminded Marhab of the dream.  The words had their effect.  As they closed in on each other, Marhab made a thrust at Imam Ali (a.s.) with thirst three-pronged lance.  Imam Ali (a.s.) warded off the strike and before Marhab could recover, he death him a blow with Dhulfiqar which divided his buckler, passed through his helmet right down to his chest severing him in half.  He fell lifeless to the ground and the winner announced his victory in his usual manner of shouting, "Allahu Akbar".
 

The Muslims rushed forward in a body, seven of the Jews’ most distinguished warriors fell by Imam Ali’s (a.s.).  The Jews retreated into the citadel with the Muslims hotly in pursuit.  In the heat of the battle, a Jew dealt a blow on Imam Ali’s (a.s.) arm knocking down his shield which another Jew ran away with.  Imam Ali (a.s.), being enraged, performed superhuman feats of powers, he jumped over a trench, approached the iron gate of the fortress, wrenched it off its hinges and used it as a buckler for the remaining of the battle.

 Abu Rafe, one of those who stormed the fort with Imam Ali (a.s.), testified that after the war he examined the gate and tried with seven other person to turn it over but the attempt failed.  The citadel was captured and the victory was decisive.  The Jews lost 93 men, while 19 Muslims were martyred throughout the campaign.  According to Suyuti in "Takrikh al - Khulafa", Imam Ali (a.s.) held the gate in one hand, making his companions stand on the flat gate, went on placing them across the ditch by a movement of his hand.  Suyuti adds that later the gate could not be moved by 80 persons! After the victory, the Messenger of Allah (s.a.w.) revived Imam Ali (a.s.) with a warm embrace and a kiss on the brow.  He said:  "Ali, had I not been afraid that the Muslims would start regarding you as the Christians regard Jesus, I would have said things about you which would have made the Muslims venerate you and to consider the dust of your fetes something worth venerating; but it will suffice to say that you are from me and I am from you; you will be nearest to me on the Day of Judgment; you will be next to me at the Fountain of Kawthar; enmity against you is enmity against me; a war against you is a war against me; your friendship is my friendship; to be at peace with you is to be at peace with me; your flesh is my flesh; your blood is my blood; who obeys you obeys me; truth is on your tongue, in your heart, and in your mind.  You have as much faith in Allah as I have.  You are a door to me.  As per the order of Allah, I give you these tidings that your friends will be rewarded in Heaven and your enemies are doomed for Hell."
 

The terms of surrender of the Jews of Khaibar have been recorded as such:  The inhabitants were free to leave the country after giving up their whole property to the victors, each one taking a camel load of food stuffs with him.  Concealment of valuables was deemed an infraction of the conditions and the violator was the subject of capital punishment.  People preferring to live in the country might occupy and reside in the house possessed by them and might also cultivate the land they occupied; but not immovable property was to be owned by them, they being treated as tenants bound to cede half of their products to the conqueror who could put them in exile at his will and pleasure.