An important secondary result of Badr and of the expeditions which preceded it was that Juhaynah and the other neighboring Red Sea tribes were now firmly allied with Medina. This meant that the coastal road to Syria was virtually barred to the Meccan caravans; and it raised the question: Would it not be possible to reduce the power of Quraysh still further by barring them from all access to the north, on the east as well as on the west? This latent danger had by no means escaped the notice of Quraysh themselves, and they had already taken some steps to strengthen their alliances with Sulaym and Ghatafan through whose territory the caravans had to pass if they took the north-easterly route to the head of the Persian Gulf and thence to to Iraq. These tribes lived in the great plain of Najd to the east of Mecca and Medina. Caravans from Mecca would make their seventh halt in the middle of the fertile tract which was occupied by Sulaym; and this tribe in particular as now urged by Quraysh to let slip no opportunity of harrying the borders of Yathrib wherever they seemed to be most vulnerable.
During the next months the Prophet had warning of three projected raids on the eastern fringes of the oasis, two by Sulaym and one by Ghatafan. In every case he forestalled them by marching out at once into their territory, and in every case they had news of his approach and vanished before he reached their point of gathering. But one of these expeditions was none the less remarkably successful. It was against the Ghatafani tribes of Tha’labah and Muharib, and this time the Prophet decided to follow the elusive Bedouin into their half hidden fastnesses in the hills to the north of Najd, with the help of a man of Tha’labah who entered Islam and offered his services as a guide. From the plain they ascended into the Muharib territory, and a sudden fall of rain drenched some of the men, including the Prophet, before they could take shelter. The Prophet withdrew a little from the others, removed his two wet garments and hung them on a tree to dry, while he himself lay down under the tree and was soon overcome by sleep. But all their movements and his in particular had been watched by many unseen eyes; and he woke to find a man standing over him with a drawn sword. It was none other than Du’thur, the chief of Muharib, who had himself been largely responsible for planning the projected raid of which the Prophet had had warning. “O Muhammad,” he said, “who will protect thee from me this day?” “God” said the Prophet, whereupon Gabriel, clothed all in white, appeared between them and, placing his hand on the man’s chest, he trust him backwards. The sword fell from his grasp, and the Prophet seized it. Gabriel vanished from Du’thur’s sight and he realized that he had seen an Angel. “Who will protect thee from me?” said the Prophet. “Nobody,” said Du’thur. “I testify that there is no god but God and that Muhammad is the messenger of God.” The Prophet handed him back his sword, which touched the man deeply. They went together to the camp, and Du’thur was instructed in the religion. Then he returned to his people, and began to summon them to Islam.
By the time that the army had returned from Najd, Ka’b ibn al-Ashraf had left Mecca, and had returned to his fortress among the Bani Nadir, not far from the outskirts of Medina. In addition to his poems urging Quraysh to take revenge for Badr, he wrote others satirizing the Prophet and his Companions; and among the Arabs a gifted poet was like a multitude of men, for his verses were repeated from mouth to mouth. IF good, he was a power for good; if evil, a power for evil, to be suppressed at all costs. The Prophet prayed: “O Lord, deliver me from the son of al-Ashraf howsoever Thou wilt, for the evil he declareth and the poems he declaimeth.” Then he said to those who were present: “Who is for me against the son of al-Ashraf, for he hath done me great injury?” The first to volunteers was a man of Aws, Muhammad ibn Maslamah of the clan of Sa’d ibn Mu’adh. The Prophet told him to consult Sa’d and four more volunteers were found. But they realized that nothing could be achieved without deception and lies, and they knew that lying was abhorrent to the Prophet; so they went to him and told him what was in their minds. He said that they were free to say whatever would serve their purpose, for deception was legitimate in warfare, being a part of its strategy, and Ka’b had declared war on them.
Ka’b was lured out of his fortress under false pretenses, and then killed. In indignation and in panic the Jews of Nadir went to the Prophet and complained that one of their chief men had been treacherously done to death, without any cause. The Prophet knew well that most of them were as hostile to Islam as Ka’b had been, and with great disappointment he had come to accept this. But it was vital to show them that if hostile thoughts were tolerable, hostile action was not. “If he had remained as others of like opinion remain,” he said, “he would not have been killed by guile. But he did us injury and wrote poetry against us; and none of you shall do this but he shall be put to the sword.” He then invited them to make a special treaty with him in addition to the covenant, and this they did.
 I.I. 551
 W. 192