Mind your own business
It is reported that ʿAbdullāh b. Mas’ūd – Allāh be pleased with him – said, “One of the worst sins is when a man says to his brother, “Fear Allāh,’ and he replies, “Worry about yourself.”
Abū Bakr Al-Daynūrī, Al-Mujālasah wa Jawāhir Al-‘Ilm article 2619.