Imam Al-Nawawi’s Riyad-us-Saliheen
Prohibition of Carrying tales of the Officers
Allah, the Exalted, says:
“… Do not help one another in sin and transgression.” (5:2)
1539. Ibn Mas`ud (May Allah be pleased with him) said: The Messenger of Allah (sallallaahu alayhi wa sallam) said, “None of my Companions should convey to me anything regarding another because I desire to meet everyone of you with a clean heart.”
[Abu Dawud and At-Tirmidhi].