General Behavior (Kitab Al-Adab)
Dawud :: Book 41 : Hadith 4902
Narrated Umm Kulthum bint Uqbah al-Umawiyyah:
The Prophet (peace_be_upon_him) 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.