The clouds upon the Syrian border gathered so rapidly that they threatened any moment to burst during the autumn of 680.  When Mahomet heard that the feudatories were massed under the bidding of Heraclius at Hims, he realised there was no time to be lost.  Eagerly he summoned his army, and expected from it the same enthusiasm for the campaign as he himself displayed.

But there was no generous response to his call.  Syria was far away, the Believers could not be convinced of the importance of the attack.  They were weary of the incessant warfare and it was, moreover, the season of the heats, when no man willingly embarked upon arduous tasks.  The Companions rallied at once to the side of their leader, and many true Believers also supported their lord, but the Citizens and the Bedouins murmured against his exactions, and for the most part refused to accompany him.

Only Mahomet’s indefatigable energy summoned together a sufficient army.  But the Believers were generous, and gave not only themselves but their gold, and after some delay the expedition was organised.

Mahomet himself led the troop, leaving Abu Bekr in Medina to conduct the daily prayer and have charge of the religious life of the city, while to Molleima were given the administrative duties.  The expedition reached the valley of Heja, where Mahomet called a halt, and there, about half-way from his goal, rested the greater part of two days.  The next days saw him continually advancing over the scanty desert ways, urging on his soldiers with prayers and exhortations, so that they might not grow weary with the long heat and the silence.  Finally he sighted Tebuk, where the rebel army was reported to be.

But by this time the border tribes had dispersed, frightened into inactivity by the strength of Mahomet’s army, and incapacitated further by lack of definite leadership.  There seemed no fighting to be done, but Mahomet was determined to make sure of his peaceful triumph.  The main force stayed at Tebuk, while Khalid was despatched to Dumah, there to intimidate both Jews and Bedouins by the size of his force and their fighting prowess.  The manoeuvre was entirely successful, and before long Mahomet had received the submission of the tribes dwelling along the shores of the Elanitic Gulf.

Meanwhile, he had recourse to diplomacy as well as the sword.  He sent a letter to John, Christian prince of Eyla, and received from him a most favourable hearing.  John accompanied the messenger back to the Prophet, where he accorded him meet reverence and regard as the leader of a mighty faith.  Between the two princes a treaty was drawn up, the text of which is extant, and very probably authentic.  It is characteristic of the whole series of treaties entered into at this time by Mahomet with the desert tribes, and as such is interesting enough to reproduce.  These treaties are given at full length in Wakidi; they differ from each other by only small details, and that drawn up for John of Eyla may be taken as fairly representative.  It is little more than a guarantee of safe conduct upon either side, and is noticeably free from any religious requirements or commissions: