The Book of Virtue, Enjoining Good Manners, and Joining of the Ties of Kinship
حَدَّثَنَا عَمْرٌو النَّاقِدُ، وَزُهَيْرُ بْنُ حَرْبٍ، قَالاَ حَدَّثَنَا سُفْيَانُ بْنُ عُيَيْنَةَ، عَنْ أَبِي الزِّنَادِ، بِهَذَا الإِسْنَادِ وَقَالَ " إِذَا ضَرَبَ أَحَدُكُمْ " .This hadith has been transmitted on the authority of Abu Zinad and he said:" When one amongst you strikes (at the face)
From Sahih Muslim, whose reports the scholars accept as authentic.