'Abdullah b. Mas'ud reported that Muhammad (ﷺ) said:Should I inform you that slandering, that is in fact a tale-carrying which creates dissension amongst people, (and) he (further) said: The person tells the truth until he is recorded as truthful, and lie tells a lie until lie is recorded as a liar.
حَدَّثَنَا مُحَمَّدُ بْنُ الْمُثَنَّى، وَابْنُ، بَشَّارٍ قَالاَ حَدَّثَنَا مُحَمَّدُ بْنُ جَعْفَرٍ، حَدَّثَنَا شُعْبَةُ، سَمِعْتُ أَبَا إِسْحَاقَ، يُحَدِّثُ عَنْ أَبِي الأَحْوَصِ، عَنْ عَبْدِ اللَّهِ بْنِ مَسْعُودٍ، قَالَ إِنَّ مُحَمَّدًا صلى الله عليه وسلم قَالَ " أَلاَ أُنَبِّئُكُمْ مَا الْعَضْهُ هِيَ النَّمِيمَةُ الْقَالَةُ بَيْنَ النَّاسِ " . وَإِنَّ مُحَمَّدًا صلى الله عليه وسلم قَالَ " إِنَّ الرَّجُلَ يَصْدُقُ حَتَّى يُكْتَبَ صِدِّيقًا وَيَكْذِبُ حَتَّى يُكْتَبَ كَذَّابًا " .
Muslim
The Book of Virtue, Enjoining Good Manners, and Joining of the Ties of Kinship • Hadith 133