وَعَن سُفيان بن أسدٍ الحضرميِّ قَالَ: سَمِعْتُ رَسُولَ اللَّهِ صَلَّى اللَّهُ عَلَيْهِ وَسَلَّمَ يَقُولُ: «كَبُرَتْ خِيَانَةً أَنْ تُحَدِّثَ أَخَاكَ حَدِيثًا هُوَ لَكَ بِهِ مُصَدِّقٌ وَأَنْتَ بِهِ كاذبٌ» . رَوَاهُ أَبُو دَاوُد
Sufyan bin Asad Hazrami (may Allah be pleased with him) narrates: I heard the Messenger of Allah (peace and blessings of Allah be upon him) say: "The greatest betrayal is that you speak to your (Muslim) brother, and he believes you to be truthful, while you are lying to him." Its chain is weak, narrated by Abu Dawood.