After the return of his victorious lieutenants, the Prophet despatched missionaries to the newly-converted tribes, in order to prevent them backsliding by introducing any of their past superstitions into the religion. One of the principal missionaries was Mu'adh ibn Jabal, who was about to set out for the Yaman. So that all should see the consideration he attached to the mission entrusted to Mu'adh, the Prophet bound a turban round his envoy's head, helped him to mount his camel, and walked by the animal's side, giving final instructions. Mu'adh confused, made as if to alight, but Mohammad stopped him. 'Remain in the saddle, O sincere friend!' he said. 'I follow the orders of Heaven and satisfy my heart. It is needful that a man performing important duties should be honoured. Ah! if only I had hopes of seeing thee again, I should cut our conversation short; but probably I now speak to thee for the last time.' Much moved, they separated; never to meet again in this world.... In the month of Zu'l-Qa'dah, the Apostle, ever mindful of the religious and political importance of the pilgrimage to Makkah, sent Abu Bakr to accomplish it at the head of three hundred Mussulmans. Scarcely had Abu Bakr reached Zu'l Holifah, when the Surah of "Bara'ah" was revealed: "_O Believers! only they who join gods with Allah (that is to say, those who in any way whatsoever, associate Allah the Only One with other divinities or persons) are unclean! Let them not therefore, after this their year, come near the Sacred Temple (of Makkah)._" (THE QUR'AN, IX, 28.) This Surah, remarkable as being the only one in the Qur'an without the introductory form: "In the name of Allah, the Merciful, the Compassionate," was of the greatest importance, in so far as the pilgrimage was concerned. It forbid all who were not Mussulmans from setting foot in Holy Territory and even nowadays this prohibition being rigorously enforced, the pilgrims of Islam are safeguarded against enemy spies, and protected from the unseemly curiosity of foreigners. This was also the final blow struck at idolatry among the Arabs who could no longer come to Makkah unless they disowned their idols. Consequently, the Prophet charged Ali to rejoin the pilgrims' caravan in all haste and recite this imperative Surah to the assembled Faithful, after the sacrifices had been made in the valley of Mina. [Sidenote: THE VALEDICTORY PILGRIMAGE (_Zul-Hijjah, in Year X of the Hegira, March A.D. 632_)]