THE ARMY OF ISLAM PROCEEDS TOWARDS TABUK
The usual practice of the Prophet was that, while performing a journey to chastise a people, who obstructed the advancement of Islam, or intended to attack the Muslims, or had evil designs against them, he did not make his aims and objects known to the officers and the soldiers, and made the army march through comparatively unfrequented routes. Thus he did not let the enemies become aware of his intentions and came upon them absolutely unawares.[1] However, in order to rout the Roman forces, who had collected on the frontiers of Syria to attack the Muslim territories, he made his aim clearly known to all concerned on the very day the general mobilization was proclaimed. The point in doing so was that the mujahids (warriors) should become aware of the importance of the journey and the hardships involved on the way, and should carry sufficient provisions with them.
Furthermore, in order to strengthen the army of Islam, the Prophet was obliged to seek help from the tribes of Tamim, Ghatfan and Tayyi' and they were residing at far-off places from Madina. In view of this the Prophet wrote letters to the chiefs of these tribes and also wrote a letter to 'Atab bin Usayd, the young Governor of Makkah, and invited the tribes as well as the Makkans to partake in this sacred jihad[2] as extension of such a general invitation was not possible secretly. Hence it was necessary that he should make the particulars of the expedition and its importance clearly known to the chiefs of the tribes so that they might place sufficient provisions and animals for riding at the disposal of their mujahids.
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1 Mughazi-i Waqidi, vol. III, page 990.
2 Biharul Anwar, vol. XXI, page 244.
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Taken From : The Message by Ayatullah Ja'far Subhani
source : sibtayn