وَحَدَّثَنِي مَالِكٌ، عَنْ عَبْدِ اللَّهِ بْنِ دِينَارٍ، قَالَ كُنْتُ أَنَا وَعَبْدُ اللَّهِ بْنُ عُمَرَ، عِنْدَ دَارِ خَالِدِ بْنِ عُقْبَةَ الَّتِي بِالسُّوقِ فَجَاءَ رَجُلٌ يُرِيدُ أَنْ يُنَاجِيَهُ وَلَيْسَ مَعَ عَبْدِ اللَّهِ بْنِ عُمَرَ أَحَدٌ غَيْرِي وَغَيْرُ الرَّجُلِ الَّذِي يُرِيدُ أَنْ يُنَاجِيَهُ فَدَعَا عَبْدُ اللَّهِ بْنُ عُمَرَ رَجُلاً آخَرَ حَتَّى كُنَّا أَرْبَعَةً فَقَالَ لِي وَلِلرَّجُلِ الَّذِي دَعَاهُ اسْتَأْخِرَا شَيْئًا فَإِنِّي سَمِعْتُ رَسُولَ اللَّهِ صلى الله عليه وسلم يَقُولُ ‏"‏ لاَ يَتَنَاجَى اثْنَانِ دُونَ وَاحِدٍ ‏"‏ ‏.‏

Malik related to me from Abdullah ibn Dinar saying, "Abdullah ibnUmar and I were at the house of Khalid ibn Uqba who was away at themarket. A man came who wanted to speak to Abdullah ibn Umar and I wasthe only other person present Abdullah ibn Umar called another man sothat we were four and said to me and the man whom he had called, 'Go alittle way off together, because I heard the Messenger of Allah, mayAllah bless him and grant him peace, say, "Two do not conversesecretly to the exclusion of another.' "' Translation Not Available

Book reference: Muwatta Imam Malik Book 56 Hadith 1826
Web reference: Muwatta Imam Malik Book 56 Hadith 13