Musnad Ahmad 268:1

Haytham ibn Kharijah narrated to us, he said: Muhammad ibn Ayyub ibn Maysarah ibn Halbas narrated to us, he said: I heard my father, he heard Khuraym ibn Fatik al-Asadi saying: "The people of Ash-Sham are the whip of Allah upon the earth; He takes vengeance through them upon whom He wills, however He wills. And it is forbidden for their hypocrites to overcome their believers, and they shall not die except in distress, or rage, or grief."