(47) Behaviour with people
كتاب تعامل الناس
(555) Chapter: When there are four people
(555) بَابُ إِذَا كَانُوا أَرْبَعَةً
Al-Adab Al-Mufrad 1170 
Ibn 'Umar reported something similar from the Prophet, may Allah bless him and grant him peace. He stated, "We said, 'If there are four?' He said, 'Then it will not harm him.'"
وَحَدَّثَنِي أَبُو صَالِحٍ، عَنِ ابْنِ عُمَرَ، عَنِ النَّبِيِّ صلى الله عليه وسلم مِثْلَهُ، قُلْنَا‏:‏ فَإِنْ كَانُوا أَرْبَعَةً‏؟‏ قَالَ‏:‏ لا يَضُرُّهُ‏.‏
Grade :  Sahih (Al-Albani) صـحـيـح  (الألباني)حكم :
Reference : Al-Adab Al-Mufrad 1170
In-book reference : Book 47, Hadith 17
English translation : Book 47, Hadith 1170