Hadith 661
661 - حَدَّثَنَا الْحُمَيْدِيُّ قَالَ: حَدَّثَنَا سُفْيَانُ، عَنْ يَحْيَي بْنِ سَعِيدٍ، عَنِ الْقَاسِمِ بْنِ مُحَمَّدٍ، أَنَّ ابْنَ عُمَرَ قَالَ لِيَحْيَي بْنِ حَبَّانَ: أَمَا تَرَوْنَ الْقَتْلَ شَيْئًا وَقَدْ قَالَ رَسُولُ اللَّهِ صَلَّي اللهُ عَلَيْهِ وَسَلَّمَ: «لَا يَتَنَاجَي اثْنَانِ دُونَ الثَّالِثِ»
Qasim bin Muhammad says: Sayyiduna Abdullah bin Umar (may Allah be pleased with them both) said to Yahya bin Habbaan: "You people do not consider killing to be anything, whereas the Noble Prophet (peace and blessings be upon him) has said: 'Two people should not converse secretly with each other, leaving out a third.'"