An-Nawawi's 40 Hadith 12
الأربعون النووية#12Not gradedOn the authority of Abu Hurayrah (may Allah be pleased with him) who said: The Messenger of Allah (peace and blessings of Allah be upon him) said, “Part of the perfection of one’s Islam is his leaving that which does not concern him.” A hasan (good) hadeeth which was related by at-Tirmidhi and others in this fashion
Scholarly Authentication
We show the most cautious grade (weakest-wins) as the overall label. Individual scholars graded it as follows:
Our source carries no per-scholar grade for this narration. Please verify on Sunnah.com or with a qualified scholar before relying on it.
In-book reference: 1:12