43. al-Mustadrak ‘alā al-Sahihain –after mentioning some reports regarding the people’s allegiance to the Commander of the Faithful (a.s.): “As for the view that claims that `Abdullah ibn `Umar, Abu Mas`ud al-Ansāri, Sa`d ibn Abi Waqqās, Abu Musā
al-Ash`ari, Muhammad ibn Maslima al-Ansāri and Usāma ibn Zaid withdrew from the allegiance, this view is of he who denies the realities of those events ….” [Then after explaining the reasons for their withdrawal, said]: “It was for these and other similar reasons that some refused to fight along with Ali (a.s.) against his enemies.”1
1.. al-Mustadrak `alā al-Sahihayn, vol. ۳, p. ۱۲۴, h. ۴۵۹۶, Ibid, p. ۱۲۷, h. ۴۶۰۵.