There is also a letter where Razi added that Ali told Muawiyah that the sahaba would flee from battles.
From amongst the Quraysh, the condition of those who had embraced Islam, was not as bad as ours. Either they had defensive alliance with the non-believers or some tribes decided to defend them despite their differences in religion. While it was the practice of the Holy Prophet (s) that whenever a battle was raged and his companions behaved cowardly or ran away from the battlefield (as in Badr, Uhud and Hunayn) which was usually the case or started making the Muslims nervous (as in Khandaq), he sent members of his family (Bani Hashim) to fight out the battle to protect his companions. These members of Bani Hashim often fought single handed and some even met martyrdom as for instance, Ubayda bin Haarith was killed in the Battle of Badr, Hamza bin Abdul Muttalib in Uhud and Ja'far bin Abu Taalib in the Battle of Mu'tah. Besides these three, there was another person (here Imam Ali (a) meant himself) who also tried his best to meet martyrdom. I could name him but the date of his death had not yet approached and he passed through these terrible ordeals alive. (Najh al Balagha, Letter 9)
The added part by Sharif Razi does not even make sense. He added that the companions ran away which made the Muslims nervous? So companions were not Muslims?
Now compare this to the Sunni Version.
As for those from the Quraysh who embraced Islam afterwards, they were relieved from the trials that we went through. Because from among them were protected tribes and individuals that had protection from their clans so that no one [from the pagan Quraysh] would do to them what they did to us. They were in asylum and were saved from being killed. This was as Allah willed. Then He ordered His Messenger to emigrate and later allowed him to fight against the polytheists. Whenever matters got tough and the battles began, he sent the people of his family to the forefront in order to protect the Companions from the heat of the battle. Thus, Ubayda [bin Harith bin al-Muttalib] was sacrificed at Badr, Hamza at Uhud, and Ja'far and Zayd at Mu'ta. The one whose name I would mention [i.e. Ali himself], more than once, sought martyrdom for the sake of Allah similar to these, yet there time was expedited and his [mine] was prolonged. Allah now grants them provision and rewards them for that which they have done. Consequently, I have not heard of or seen anyone from the people who was more sincere to Allah through obedience to His Messenger or more submissive to the Messenger in obedience to his Lord, more steadfast during hardships and times of distress than those who I have just named! Although, there were good people amongst the Muhajirun as well, may Allah reward them. (al-Baladhuri and the Wa'qat Siffin by al-Minqari.)