Jaun bin Huwi was Abuzar's slave whose life history depicts the training of Abuzar. According to the Mamaqani, the genealogy of Jaun is as under:
Jaun bin Huwi bin Qatadah bin A 'war bin Sa 'idah bin 'Awf bin Ka'b bin Huwi Habashi (Tanqihul Maqal vol. 1).
It is written about him that by race he was an African and was in the ownership of Fazl bin Abbas bin Abdul Muttalib, from whom Ali bought him for 150 golden coins and he gave him as gift to Abuzar. By this Ali wanted Jaun to serve Abuzar.
Accordingly, Jaun rendered a meritorious service to Abuzar who was extremely happy with him. Jaun served Abuzar as well as received the benefit of his company. He observed every aspect of Abuzar's character very care- fully and was deeply impressed by it.
Of course Jaun left no stone unturned to serve Abuzar. Also there was no place where he did not have the honour of Abuzar's company except at Rabzah where his presence is not testified by any reliable book of history. Anyway, Jaun served Abuzar as best as he could. After the departure of Abuzar to Rabzah he stayed back in the service of Ali. After Ali's martyrdom he served Imam Hasan and when in the year 50 A.H. Imam Hasan was martyred he came to serve Imam Husayn.
In short, he rendered sincere services to the virtuous personalities all his life. When Imam Husayn left his hometown first for Mecca and then for Karbala during the month of Rajab in the year 60 A.H. Jaun was also with him during this journey.
Allamah Majlisi and Allamah Samawi write on the authority of Sayyid Razi Daudi that when fighting started at Karbala on the l0th of Muharram in the year 61 A.H. Jaun came to. Imam Husayn and desired his permission to fight. Imam Husayn said, "You have my permission. But O Jaun! You have stayed with me to live in peace and no wish to be killed!" At these words Jaun fell at the feet of Imam Husayn and said, "O my master, I am not one o those who flatter you during the period of peace and comfort, and leave you in times of adversity. O my master There is no doubt that my sweat gives a horrid smell, my lineage is not noble, and my colour is black, but with your blessing my sweat will become fragrant, my lineage will become noble and my colour will get white in Paradise. By Allah, I will not forsake you unless my blood mixes up with your blood".
At last Imam Husayn accorded him permission. Jaun came to the battlefield, started fighting and recited the following "rajaz" (epic verses):
"O you damned ones! Did you see the fight of the African slave?
See how he fights in support of the Progeny of the Holy Prophet!"
After the recital of the "rajaz" Jaun made a violent attack upon the enemy, fought continuously till he killed twenty five enemies and attained martyrdom. (Muntahul Amal).
Muhammad bin Abi Talib Makki has written that when Jaun was martyred Imam Husayn came to his dead body, placed his head in his lap and prayed to Allah, "O Allah! Brighten the face of Jaun, make his sweat fragrant and give him a place with the virtuous ones in .Heaven, so that he may stay with Muhammad and his Progeny (Ahlul Bayt)".
Scholars quote Imam Muhammad Baqir who quotes his father Imam Zaynul Abidin as saying that a few days after Bani Asad had buried the dead bodies of the martyrs and gone away, they found the dead body of Jaun whose face was bright and whose dead body gave out the sweet fragrance of musk. (Absarul 'Ain, p. 165, printed Hyderabad Deccan, 1357 A.H. & Biharul Anwar, vol. 1).
In short, this faithful slave of Abuzar laid down his life for his master, Imam Husayn, fighting against Yazid bin Mu'awiyah, the Umayyad tyrant, with courage, boldness and bravery and attained martyrdom. It is an established fact that immediately after the demise of the Holy Prophet, all his teachings and admonitions was disregarded by the hypocrites, whose only aim was to secure worldly gains and set the Prophet's teachings at naught.
Some of the companions of the Holy Prophet who were staunch believers in Islam, and were imbued with his and his Ahlul Bayt's love, rose up to fight, tooth and nail, against these evil forces. They were the true followers of Prophet Muhammad and his Ahlul Bayt and took guidance from what they had said and done. There were other companions also who assumed power and authority in the name of Islam. But instead of serving the cause of Islam, they misused Islam's name and wealth for their personal and family aggrandizement. They squandered away the wealth of the nation as if it was their own property. Among the companions there was one who went so far as to say: "By Allah, until I have exterminated the name of Prophet Muhammad from the face of the earth I shall have no peace" (Murujuz Zahab by Mas'udi, vol. 3, p. 454, printed by Oarul Andalus Press). This resulted in the coming into being of a new trend i.e. kingship, which brought about horrors in the years to come. Such a deviation from Islam was intolerable for the true companions who could not refrain from uttering the truth even at the cost of their life.
Abuzar is a clear example of forbearance, Steadfastness, and courage, which he showed when tortures were inflicted on him so much so that he courted death but did not give up uttering truth, as had been predicted by the Holy Prophet. His example was followed by his slave Jaun also on the sands of Karbala when he valiantly sacrificed his life on the side of the Holy Prophet's grandson Husayn.