The people of Medina were forced to prepare an army (to fight against the people of Sham during the
caliphate of `Abdullah bin Az-Zubair at Mecca), and I was enlisted in it; Then I met `Ikrima, the freed
slave of Ibn `Abbas, and informed him (about it), and he forbade me strongly to do so (i.e. to enlist in
that army), and then said, "Ibn `Abbas informed me that some Muslim people were with the pagans,
increasing the number of the pagans against Allah's Messenger (ﷺ). An arrow used to be shot which would
hit one of them (the Muslims in the company of the pagans) and kill him, or he would be struck and
killed (with a sword)." Then Allah revealed:--
"Verily! as for those whom the angels take (in death) while they are wronging themselves (by staying
among the disbelievers)" (4.97) Abu AlAswad also narrated it.
Sahih al-Bukhari Book 65, Hadith 118