The Holy Prophet sent Mus`ab ibn `Umayr to them.

The Holy Prophet sent Mus`ab ibn `Umayr to them.[^11] Due to his hard work in propagation, a great number of people accepted the Islamic faith. In Mecca, the chiefs opposed Islam; but the youth and the deprived ones accepted it as religion. However, in Yathrib, it was the other way round; the chiefs pioneered to adopt Islam and people naturally followed their suit. This was one of the factors for the spread of Islam in this city.

The Second Treaty of `Aqabah In the thirteenth year of prophethood and at the Hajj ceremony, a group of seventy-five people, eleven of whom were from Aws and two women, entered Mecca. On the twelfth of Dhu’l-Hijjah, the second treaty of `Aqabah was concluded with a lot of precautions. The signers pledged that if the Holy Prophet emigrated to their city, they would protect him like their own relatives and children and fight anybody who would fight against him.

For this reason, this treaty came to be called bay`at al-harb (the pledge of war). At the end of this meeting, the signers elected twelve representatives to manage their affairs upon their return to Yathrib.[^12] The initial Stages of emigration to Yathrib Despite all the precautions that the Holy Prophet and the people of Yathrib had taken, Quraysh found out the secrets behind this treaty. Consequently, they endeavored to arrest the treaty signers.

Since those who paid homage to the Holy Prophet had left Mecca in time, they could flee to safety except for one who was arrested. After the departure of the people of Yathrib, Quraysh increased their pressure on Muslims, because they realized that the Holy Prophet had safeguarded a stronghold in Yathrib; they therefore increased their pressures on Muslims.

Once again, life in Mecca had become intolerable.[^13] For this reason, the Holy Prophet ordered Muslims to emigrate to Yathrib, telling them, “Go to Yathrib; God will provide you with brethren and a safe place. ”[^14] For two and a half months, (i.e. from the middle of Dhu’l-Hijjah up to the end of safar)[^15] Muslims gradually headed for Yathrib despite all hardships that Quraysh put in their way.

Hence, no Muslim remained in Mecca except for the Holy Prophet, Imam `Ali, Abu-Bakr and some others. In the history of Islam, those Muslims who emigrated to Yathrib are called muhajirun (Emigrants) and those who helped out the Holy Prophet in Yathrib are called ansar.