Among them is al-Bara bin Ma'rur bin Sakhr bin Khansa (may Allah be pleased with him): the first of the leaders to speak was al-Bara bin Ma'rur

It is narrated from Mahmud bin Labid (may Allah be pleased with him) that when Abu al-Haysar Anas bin Rafi' came to Makkah, accompanied by some young men of Banu Abd al-Ashhal, among whom was Iyas bin Mu'adh, they had come to make a treaty of alliance with Quraysh against their people, the Khazraj. When the Messenger of Allah (peace and blessings be upon him) heard about them, he (peace and blessings be upon him) came to them, sat with them and said: "Would you like something better than the purpose for which you have come?" They asked: What is that? He (peace and blessings be upon him) said: "I am the Messenger of Allah. Allah has sent me to His servants to call them to worship Allah alone and not to associate anything with Him, and He has revealed the Book to me." Then he (peace and blessings be upon him) told them about Islam and recited the Qur'an to them. Iyas bin Mu'adh, who was still a young boy, said: O my people, by Allah, this is far better than the purpose for which you have come here. Abu al-Haysar then took a handful of dust from the ground, threw it in the face of Iyas bin Mu'adh and said: Leave us alone; by my life, we have not come for this. So Iyas fell silent. Then the Messenger of Allah (peace and blessings be upon him) left, and they returned to Madinah. Then the Battle of Bu'ath took place between the Aws and the Khazraj. The narrator said: Shortly after that, Iyas bin Mu'adh passed away. Mahmud bin Labid said: Those of my people who were present at his death told me that he continued declaring Allah's oneness (tahlil), magnifying Him (takbir), praising Him (tahmid) and glorifying Him (tasbih) until he died. So they had no doubt that he died a Muslim, for what he had heard from the Messenger of Allah (peace and blessings be upon him) in that gathering had made Islam permeate his whole being.
This hadith is sahih (authentic) on the condition of Imam Muslim, and the two Shaykhs did not record it.

Yahya bin Abdullah narrates from his father, who narrates from his grandfather, that Sayyiduna al-Bara' bin Ma'rur (may Allah be pleased with him) died in the month of Safar, one month before the Prophet (peace and blessings be upon him) arrived in Madinah, and he was the first of the Nuqaba' (chiefs) to speak.