From the first years of his Prophethood, Prophet Muhammad showed great efforts to convey the message to those coming to Makka for pilgrimage as well as those coming to the city’s fairs for trade. The most fruitful of these contacts were those he made with the people of Yathrib (Madina). In the pilgrimage season of his eleventh year of Prophethood (620), the Prophet encountered a group of six people from Yathrib in ‘Aqaba, a secluded place in Mina, and spoke to them about Islam. These people, all members of the Khazraj tribe, accepted and became Muslim. Among them, As’ad ibn Zurara promised that he would return to Yathrib, convey the new religion to both his own tribe and to the Aws tribe, and meet the Prophet again at ‘Aqaba one year later. Many people became Muslim as a result of the great efforts of this group of six Yathribites who formed the essence of the Ansar community and whose services to Islam were significant.
In the following year, the twelfth year of Prophethood (Dhu'l-Hijjah/July 621), twelve people, ten from the Khazraj and two from the Aws tribe, secretly met with the Prophet at ‘Aqaba. The Yathribites swore allegiance to the Prophet, affirming that they would not associate partners with God, not steal or commit fornication or adultery, that they would not kill their children, not slander, and that they would honor the Messenger’s instructions and commands. This pledge is known as the “First ‘Aqaba Allegiance.” Prophet Muhammad send Mus’ab ibn ‘Umayr back with this delegation to Yathrib so that he could teach the people of Yathrib the Qur’an and Islam, invite others to Islam, and lead them in prayer.
In the span of just one year the efforts of Mus’ab ibn ‘Umayr, residing in the house of As’ad ibn Zurara at the time, were such that Yathrib’s leading figures, including chieftains of the Aws Sa'd ibn Mu'adh and Usayd ibn Khudayr, had become Muslim and the city had become a land of Emigration. And so, in the pilgrimage season of the thirteenth year of Prophethood (622), seventy-five Yathribite Muslims, two of them women, joined a convoy of pilgrims to Makka, some of them not yet having accepted Islam. At the completion of the pilgrimage they met with the Prophet once again at ‘Aqaba, and again in secret. The Prophet had gone to ‘Aqaba with his uncle ‘Abbas, who had not yet become Muslim. Upon the Yathribites inviting him to their city, Prophet Muhammad first recited some verses from the Qur’an and then gave them words of encouragement in relation to the need for them to hold fast to the religion of Islam. He then listed the terms of the second pledge of allegiance: That they would protect the Prophet Muhammad and the Makkans in the event that they emigrated as they would protect their own lives, children, wives and property; that they would remain committed to the Prophet’s instructions in times of ease as well as difficulty; that they would provide financial support in times of abundance as well as hardship; that they would enjoin the good and forbid the evil; and that they would fear no one in their devotion to truth and justice. Every single Yathribite agreed to these stipulations and pledged their commitment to the Prophet. Prophet Muhammad requested them to select twelve representatives (naqib) from among them to facilitate communication with him. As such, they chose nine members of the Khazraj and three from the Aws tribes. The Prophet assigned from the Khazraj, representative of the Banu Najjar As’ad ibn Zurara as the head of the other twelve representatives. Due to the fact that the Second ‘Aqaba Allegiance encompassed matters dealing with defense, it also came to be known as the Pledge of War (Bay’at al-Harb).
In actual fact, Yathrib was located at a strategic point that would enable developments to the detriment of the Quraysh; Caravans travelling to Syria, Palestine and Iraq from the north had no other option than to pass through the surrounds of this city. On the other hand, many lives were lost in the last battle of the 120-year war between the Aws and the Khazraj tribes at Bu'ath. It was hoped that the hostility between them would come to an end by virtue of the new religion. Thus, ‘A’isha observed: “Bu'ath was a day prepared for God’s Messenger.”