The one case where saying more than you know is not lying
Narrated by a woman through her son.
لَيْسَ بِالْكَاذِبِ مَنْ أَصْلَحَ بَيْنَ النَّاسِ فَقَالَ خَيْرًا أَوْ نَمَى خَيْرًا
Laysa bi-l-kādhibi man aṣlaḥa bayna-n-nāsi fa-qāla khayran aw namā khayrā
He is not a liar who puts things right between people, saying something good or passing on something good.
Where this comes from
Namā means to carry a report from one side to the other. Ordinarily that is the word used for the gossip that breaks people apart. Here it is the same verb doing the opposite job, and the ruling on it is reversed with it.
The full narration
Humaid b. 'Abd al-Rahman quoted his mother as saying:The Prophet (ﷺ) said: He who forged in order to put things right between two persons did not lie. The version by Ahmad ibn Muhammad and Musaddad has: The liar is not the one who puts things right between people, saying what is good and increasing good
Source
Sunan Abī Dāwūd · 4920
- Al-Albani: Sahih
- Muhammad Muhyi Al-Din Abdul Hamid: Sahih
- Shuaib Al Arnaut: Sahih
- Zubair Ali Zai: Sahih Bukhari (2692) Sahih Muslim (2605)