Leaving what does not concern you

On the authority of Abu Hurayra (may Allah be pleased with him), that the Prophet (may Allah bless him and grant him peace) said: "Part of a man's excellence in Islam is his leaving what does not concern him."

A hasan hadith, related by at-Tirmidhi and others.

[at-Tirmidhi 2317; Ibn Majah 3976]