حَدَّثَنَا سُفْيَانُ عَنْ عَبْدِ اللَّهِ بْنِ دِينَارٍ عَنِ ابْنِ عُمَرَ عَنْ النَّبِيِّ صَلَّى اللَّهُ عَلَيْهِ وَسَلَّمَ قَالَ إِذَا كُنْتُمْ ثَلَاثَةً فَلَا يَتَنَاجَ اثْنَانِ دُونَ الثَّالِثِ وَقَالَ مَرَّةً إِنَّ النَّبِيَّ صَلَّى اللَّهُ عَلَيْهِ وَسَلَّمَ نَهَى أَنْ يَتَنَاجَى الرَّجُلَانِ دُونَ الثَّالِثِ إِذَا كَانُوا ثَلَاثَةً
مسند امام احمد بن حنبل · Hadith 4564
It was narrated from Ibn 'Umar from the Prophet (PBUH) who said "If you are three, two should not converse privately to the exclusion of the third." And on one occasion he said: The Prophet (PBUH) forbade two men to talk privately to the exclusion of the third, if they are three."
Sanad
حَدَّثَنَا سُفْيَانُ عَنْ عَبْدِ اللَّهِ بْنِ دِينَارٍ عَنِ ابْنِ عُمَرَ