إِنَّ مِنْ حُسْنِ إِسْلَامِ الْمَرْءِ تَرْكَهُ مَا لَا يَعْنِيهِ

Verily, from the perfection of Islam is that a person leaves what does not concern him.

Source: Sunan At-Tirmidhi 2318, Grade: Hasan