The Army of Islam at Tabuk
Arriving at Tabuk and camping there, the Muslim army was ready to face the enemy. There, the Messenger of All‚h [pbuh] delivered an eloquent speech that included the most inclusive words. In that speech he urged the Muslims to seek the welfare of this world and the world to come. He warned and cherished them and gave them good tidings. By doing that he cherished those who were broken in spirits, and blocked up the gap of shortage and mess they were suffering from due to lack of supplies, food and other substances.
Upon learning of the Muslimsí march, the Byzantines and their allies were so terrified that none of them dared set out to fight. On the contrary they scattered inside their territory. It brought, in itself, a good credit to the Muslim forces. That had gained military reputation in the mid and remote lands of Arabian Peninsula. The great and serious political profits that the Muslim forces had obtained, were far better than the ones they could have acquired if the two armies had been engaged in military confrontation.
The Head of Ailah, Yahna bin Rawbah came to the Messenger of All‚h [pbuh], made peace with him and paid him the tribute (Al-Jizya). Both of Jarbaí and Adhruh peoples paid him tribute, as well. So the Messenger of All‚h [pbuh] gave each a guarantee letter, similar to Yahnaís, in which he says:
The Messenger of All‚h [pbuh] dispatched Khalid bin Al-Waleed at the head of four hundred and fifty horsemen to ĎUkaidir Dumat Al-Jandal and said to him: "You will see him hunting oryxes." So when Khalid drew near his castle and was as far as an eye-sight range, he saw the oryxes coming out rubbing their horns against the castle gate. As it was a moony night Khalid could see Ukaidir come out to hunt them, so he captured him ó though he was surrounded by his men ó and brought him back to the Messenger of All‚h [pbuh], who spared his life and made peace with him for the payment of two thousand camels, eight hundred heads of cattle, four hundred armours and four hundred lances. He obliged him to recognize the duty of paying tribute and charged him with collecting it from Dumat, Tabuk, Ailah and Taimaí.
The tribes, who used to ally the Byzantines, became quite certain that their dependence oinn their former masters came to an end. Therefore they turned into being pro-Muslims. The Islamic state had therefore enlarged its borders to an extent that it, touched the Byzantinesí and their agentsí borders. So we see that the Byzantine agents role was over.