It is recorded for example in some of the Sahihs that...
It is recorded for example in some of the Sahihs that Abdul-Rahman Ibn Abu Omeirah reported that the Prophet prayed for Muawiya saying: "God make him well-guided and make him lead people to the right road." It is also reported in a Sahih that the Messenger said to Ammar Ibn Yasir: "Ammar be cheerful the aggressor party will kill you.". Yet the party that killed Ammar was the party of Muawiya.
When Muawiya is the head of the aggressors he would not be well-guided nor could people be led through him to the right road. A hadith commending a man such as Muawiya cannot be a security against deviation. It would be rather a cause of confusion. A man that waged against ‘Ali the Imam of the truth and the brother of the Prophet a war in which tens of thousands of Muslims were killed cannot be a guide to the right road.
To make what Ibn Hisham reported logically acceptable we have to understand from the word "Sunnah " the statement of the Prophet and his actions which are known to have come from him. These represent a security against deviation if we follow them. But that which is known of his statements and actions are very little because most of the hadiths were not reported by numerous reporters in every link of its chain of narration; they were rather reported by one or two or a few reporters.
Many of these hadiths contradict each other. Therefore we cannot acquire certainty through those hadiths about what the Messenger said or did. There is only one logical way through which we can be certain of Sunnah of the Prophet: The Prophet himself could inform us of a reliable source through which we know exactly what he said and did.
The first hadith which was reported by more than twenty companions informs us of that reliable source namely: the members of the House of the Prophet who knew the interpretation of the Book of God and the instructions of the Messenger completely. By this the hadiths of Al-Termathy and Ibn Hisham would be agreeing with each other and explaining one another. ‘Ali possessed the knowledge of the Qur'an and the words and the deeds of the Prophet and their interpretations.
The Muslims could have avoided deviations if they were to follow his interpretation and assist him in communicating his knowledge to the nation. However the other outstanding event which took place during the last year of the life of the Messenger has made this matter crystal clear. The event was fully expressive concerning the elements of security against deviation.