When the men who took the pledge at Aqabah finished performing Hajj, the Prophet sent Mus’ab bin Umayr along with them to teach them the Qur’an. In Yathrib, Mus’ab stayed with Abu Umama Asad bin Zurara. The two directed their efforts towards teaching non-Muslims about Islam. One day as Umayr and Abu Umama sat in an orchard, Sa’d bin Mu’adh, the chieftian of the Aus tribe, spotted them. He said to his cousin, Usayd bin Hudhayr, “Go and rebuke those two who have come to deceive our weak.” Weapon in hand, Usayd approached the two Muslims. Asad saw him and warned Mus’ab, “Here comes a chieftain.” “Why are you here?” Usayd thundered. “Do you intend to deceive our weak? Keep away if you value your life!”

Mus’ab was not intimidated. “Why don’t you sit and listen? If you like what we say, accept it; if you dislike it, don’t.” “That sounds fair,” siad Usayd cautiously. He put away his weapon and sat down. Mus’ab explained the basic principles of Islam and then recited some verses of the Qur’an. Usayd found himself agreeing with everything Mus’ab said, so he embraced Islam. He then returned to Sa’d bin Mu’adh, who now had to be convinced. “I talked to them,” Usayd said to Sa’d carefully, “and found nothing objectionable in what they say. Still, I forbade them to talk to anyone else. By the way, I managed to find out that Banu Haritha are planning to kill Asad bin Zurara because he is our cousin. They want to break the covenant.”

Usayd’s ploy worked. Sa’d became angry and made his way to Mus’ab and Asad. Mus’ab told him the same thing he had told Usayd, and Sa’d agreed to listen. When Mus’ab finished explaining the principles of Islam, Sa’d too became Muslim. His love for the Prophet and his faith made him one of the more distinguished Companions of the Prophet .

His new faith surging in his heart, Sa’d returned to his people and said, “O Banu Abdul Ash’hal! What do you know about me as a man among you?” They answered in one voice, “You are our chief and the wisest man among us!”

Sa’d said, “Well, I will not talk to the families of those who do not believe in Allah and his Prophet.” As a result of this, every man and woman in the tribe became Muslim except for Usayram, who became Muslim in the Battle of Uhud. He was martyred in the battle before he had even performed one prostration as a Muslim.

Mus’ab bin Umayr returned to Makkah before the next Hajj. His account of how Allah had guided the people of Yathrib to Islam delighted the Prophet immensely.