Righteousness is good character

On the authority of an-Nawwas ibn Sam'an (may Allah be pleased with him), that the Prophet (may Allah bless him and grant him peace) said: "Righteousness is good character, and sin is what wavers in your soul and which you would hate for people to find out about."

Related by Muslim. On the authority of Wabisa ibn Ma'bad (may Allah be pleased with him): “I came to the Messenger of Allah (may Allah bless him and grant him peace) and he said: ‘You have come to ask about righteousness and sin?’ I said: ‘Yes.’ He said: ‘Consult your heart. Righteousness is that about which the soul feels at ease and the heart feels tranquil, and sin is what wavers in the soul and moves to and fro in the breast, even though people give you their opinion again and again.’” A hasan hadith, related by the imams Ahmad and ad-Darimi in their Musnads with a good chain.

[Muslim 2553]