Mus'ab r.a was so successful in his mission to teach Islam to the tribes in Yathrib, that the way was being prepared for the great migration (Hijrah) for the Muslims from Mecca and the city of Yathrib was soon to become the base for the Islamic state and the flourishing of Islam in the world. Seventy-five Muslims from Yathrib eventually travelled with Mus'ab to Mecca during the pilgramage period. They took a solemnly undertook an oath to defend the Prophet at all cost and to remain firm in their faith. The second ba'yah or pledge called the Pledge of War was also undertaken by the Yathrib Muslims.