It is reported that Bilāl b. Saʿd – Allāh have mercy on him – said:
A brother who, whenever you meet him, points out to you one of your faults (for you to correct yourself) is better for you than a brother who, whenever you meet him, puts a dīnār (money) in your hand.
Abū Bakr Al-Daynūrī, Al-Mujālasah wa Jawāhir Al-ʿIlm no. 1428.
Bilāl b. Saʿd – Allāh have mercy him – said:
When a sin is hidden it harms only the perpetrator, but if it is made apparent and not rectified, it harms all the people.
Ibn Waḍḍāḥ, Al-Bidʿah #287.
Bilāl b. Sa’d – Allah have mercy on him – said:
Do not think about how small the sin is, but think about who you have just disobeyed.
Ibn Al-Mubārak, Al-Zuhd wa Al-Raqā`iq Vol.1 p150.