From: http://www.salafitalk.com/entries/26-The-Noble-Companion-Mus-ab-bin-Umayr
His name is Mus’ab bin ‘Umayr bin Haashim bin ‘Abd Manaaf bin ‘Abd ad-Daar bin Qusayy bin Kilaab.
He is the Chief Martyr, from the first and foremost to accept Islaam. He was from the tribe of Quraish, and he participated in the battle of Badr.
Al-Baraa bin ‘Aazib said:
The first to come to us [in Madeenah] from the Muhaajireen was Mus’ab bin ‘Umayr, so we said: “What has the Messenger of Allaah done?” So he replied: “He is at his place, and his Companions are following behind me.” Then after him there came ‘Amr bin Ummi Maktoom, from the people of Banee Fihr – and he was blind. (He then mentioned the hadeeth).
Al-A’mash from Abee Waa’il from Khabbaab, who said:
“We migrated alongside Allaah’s Messenger (salallaahu ‘alaihi wassallam), and from us were those who passed away in His cause not having consumed anything from His reward [in this world]. From them was Mus’ab bin ‘Umayr, who was killed on the day of the Battle of Uhud – he did not leave behind anything except a cloak, and if we covered his head with it, then his feet would remain uncovered, and we covered his feet, then his head would remain uncovered. So Allaah’s Messenger (sallallaahu ‘alaihi wasallam) said: “Cover his head with it, and cover his feet with idhkhir (a shrub).” And from us were those whose fruits [of reward] have been hastened for him and he is tried by them.
Ibn Ihaaq stated that Mus’ab bin ‘Umayr (radhiyallaah ‘anhu) was killed by Ibn Qami’ah al-Laythee who thought that he killed the Messenger of Allaah (salallaahu ‘alaihi wassallam) saying to Quraish: “I have killed Muhammad.”
From Shu’bah, from Sa’d bin Ibraaheem, who heard his father saying: Abdur-Rahmaan bin Awf was brought some food and he began to cry.He said,
“Hamzah has been killed, and nothing was found to shroud him except a single garment. And Mus’ab bin Umayr was killed and nothing was found to shroud him with except a single garment. I have feared that perhaps our good things from our worldly life have been hastened for us.” And then he cried (again). Reported by al-Bukhaaree.
See Siyar A’laam an-Nubalaa (6143), Tabaqaat Ibn Sa’d (3/1/81-86), al-Jarh wat-Ta’deel (8/303), Hilyah al-Awliyaa (1/106-107), Tabaqaat al-Quraa (2/299), al-Isaabah (9/208-209).
So Mus’ab bin ‘Umayr (radhiyallaahu ‘anhu) was from the earliest of those who entered into Islaam, he strove in the Path of Allaah, and was eventually martyred at the battle of Uhud. The ‘ulamah mention that he was the first envoy of Allaah’s Messenger (salallaahu ‘alaihi wassallam) to Madinah. He embraced Islaam in Daar al-Arqam. He initially concealed his conversion from his mother and his people due to the harm they would cause. When they realised he had become a Muslim, they took hold of him and kept him captive. He remained in that state until he migrated to Abyssinia. When he returned from Abyssinia, he migrated once again, this time to Madinah – after the first pledge of al-‘Aqabah so as to teach the people Qur’aan and lead them in prayer.
I (Abu Khadeejah) say: Mus’ab bin ‘Umayr (radhiyallaahu ‘anhu) was an ‘Aalim of the Deen of Islaam, a teacher for the people of Madinah and a Reciter of the Book of Allaah. Indeed he is an example for generation after generation until the Hour is established. Whatever I have said other than this, due to an error or a slip on my behalf, i.e. that he was not a Scholar but he knew only that which the Messenger, salallaahu ‘alaihi wassallam, taught him – then this is slip from myself and Shaitaan, and I seek refuge with Allaah from that. And we ask Allaah not to take us to account for that which is uttered out of forgetfulness and error, and I seek His forgiveness.
Narrated ‘Ubaidullaah bin Ahmad, with his chain back to Yunus bin Bukayr from Ibn Ishaaq from Yazeed bin Abee Habeeb who said:
“When the people left Allaah’s Messenger (salallaahu ‘alaihi wassallam) – meaning on the night of the first pledge of al-‘Aqabah – he sent Mus’ab bin ‘Umayr (radhiyallaahu ‘anhu) along with them.”
Ibn Ishaaq said: ‘Aasim bin ‘Umar bin Qataadah narrated to me that Mus’ab bin ‘Umayr used to lead them (Aws and Khazraj) in prayer [in Madinah]…
He also said that ‘Ubaidullaah bin Abee Bakr bin Hazm and Ubaidullaah bin al-Mugheerah bin Mu’aiqeeb both said: The Messenger (salallaahu ‘alaihi wassallam) sent Mus’ab bin Umayr with the twelve who pledged allegiance at al-‘Aqabah the first time around to give their people understanding [of the Deen], and to recite to them the Qur’aan. He stayed at the house of As’ad bin Zuraarah – and he was named in Madinah as the Reciter. It is said that he was first to gather the people together to pray Jumu’ah in Madinah. Usaid bin Hudair and Sa’d bin Mu’aadh both embraced Islaam at his hands – and that would be sufficient as a virtue and a legacy in Islaam.
He participated in the battle of Badr alongside Allaah’ Messenger (salallaahu ‘alaihi wassallam) and the battle of Uhud and with him was the standard of Allaah’s Messenger (salallaahu ‘alaihi wassallam) – and he was martyred at Uhud. It is said that his age was forty or slightly more when he passed away.
It is said that as a youth he was a handsome, well-dressed young man – his father used to bestow gifts upon him plentifully, his mother would dress him in the best clothing that could be bought. He was the most beautiful smelling (well-perfumed) of the people of Makkah. Yet this noble young man saw the beauty of Islaam, and the Tawheed that Islaam calls to, and he followed the Messenger (salallaahu ‘alaihi wassallam) – he was from the earliest and foremost ones who embraced Islaam and strove in Allaah’s cause in teaching and in Jihaad until he was martyred and shrouded in a single garment – radhiyallaahu ‘anhu.
Was-sallallaahu ‘ala Muhammad wa ‘ala aalihi wa sahbihi wasallam, wal-hamdulillaahi rabbil-‘aalameem.
Abu Khadeejah ‘Abdul-Waahid.