The failure of the nominees of Ali to assume office as the Governors of Syria and Kufa was a great challenge for Ali. Musa, the Governor of Kufa, tried to temporize though he acknowledged the authority of Ali. In Syria the story was different. To start with the stand of Muawiyah was that he would acknowledge the caliphate of Ali after those who were responsible for the assassination of Othman had been brought to book. Ali sent an emissary to Muawiyah to explain to him the position. He assured him that every possible effort would be made to trace the murderers of Othman. He observed that this would need some time. He wanted the support of Muawiyah in tracing the culprits. He advised that in the meantime, Muawiyah should step aside from the office of the Governor and cooperate with the nominee of the central government in the interests of the solidarity of Islam. He pointed out that any dissentions among the Muslims at the stage would work to the advantage of the enemies of Islam.
Muswiyah detained the emissary of Ali for over three months. In the meantime he whipped up his propaganda campaign exploiting the murder of Othman. He sent his agents to Makkah, and other parts of the country to relate the story of the assassination of Othman in pathetic terms, and win the sympathy of the people. As the propaganda gathered momentum Ali came to be accused of being an accomplice in the murder of Othman. The burden of the propaganda was that as the hands of Ali were dyed with the blood of Othman he was not qualified to be the Caliph, and those who had withheld their allegiance to him were justified in their refusal to acknowledge his authority.
After three months, Muawiyah allowed the emissary of Ali to return to Madina. He said that he would be sending his own emissary with a message for Ali. The letter of Muawiyah was brought to Madina by a Bedouin chief Kabisa. The cover bore the address "From Muawiyah to Ali". When the cover was opened, it contained a blank paper with no writing thereon. In a fit of anger, Ali asked the bearer what did that mean? Kabisa pleaded for the safety of his life before he could answer the question. Ali said that he was free to speak, and he had his promise of safety. On this assurance the messenger said: "Know you then that there are no less than 60,000 Syrians whose beards are wet with tears, and who are rallying around Othman's bloody shirt which they have made their war standard, have armed themselves and are bent on avenging the murder of Othman".
On hearing these words the anger of Ali knew no bounds but he controlled his anger and said, "This is pure sedition." Someone from among the congregation shouted "Kill the Syrian messenger for his impudence," At this Kabisa took to heels and retorted, "Four thousand chosen warriors are near at hand. Take care of your homes and hearths." Ali said to the envoy, "Be gone, for I have promised you the safety of your life".
Kabisa went away, but the defiant attitude of Muawiyah was a great challenge for Ali. To those of the Muslims who were present in the mosque, Ali addressed in the mosque in the following terms: "Beware! Satan has gathered his forces. His army is multiplying. By his wiles, Satan is attracting the people to him. Their propaganda is a tissue of lies. Their accusations against me are most unjust and unfair. They demand from me the right which they themselves had abandoned. They demand from me blood for blood which they themselves have shed. Their repeated demand for taking vengeance from the murderers of Othman is like demanding milk from a woman which has dried up. He who invites me to war should know that under all circumstances I will follow the teachings of the Holy Quran and the Prophet. If they refuse to abide by the injunctions of Islam the sword which helps the upholders of truth, and destroys the mischief makers would decide the issue. It is surprising that in spite of their stand on falsehood they give me the challenge of war. May God curse them. War can never frighten me to abandon the truth. I am not afraid of death. I will live for Islam and die for Islam. "