(45) باب لاَ يَتَنَاجَى اثْنَانِ دُونَ الثَّالِثِ
Narrated `Abdullah:
the Prophet (ﷺ) said "When three persons are together, then no two of them should hold secret counsel excluding the third person."
Reference: Sahih al-Bukhari 6288
In-book reference: Book 79, Hadith 60
USC-MSA web (English) reference(deprecated numbering scheme): Vol. 8, Book 74, Hadith 303