Good character, modesty, controlling anger and excellence in all things.
On the authority of Abu Hurayrah (may Allah be pleased with him) who said: The Messenger of Allah (peace and blessings of Allah be upon him) said, “Part of the perfection of one’s Islam is his leaving that which does not concern him.”
On the authority of an-Nawas bin Sam’an (may Allah be pleased with him), that the Prophet (peace and blessings of Allah be upon him) said: Righteousness is in good character, and wrongdoing is that which wavers in your soul, and which you dislike people finding out about. [Muslim] And on the authority of Wabisah bin Ma’bad (may Allah be pleased with him) who said: I came to the Messenger of Allah (peace and blessings of Allah be upon him) and he (peace and blessings of Allah be upon him) said, “You have come to ask about righteousness.” I said, “Yes.” He (peace and blessings of Allah be upon him) said, “Consult your heart. Righteousness is that about which the soul feels at ease and the heart feels tranquil. And wrongdoing is that which wavers in the soul and causes uneasiness in the breast, even though people have repeatedly given their legal opinion [in its favour].”
About this text. Arabic and English text from the hadith-api project (github.com/fawazahmed0/hadith-api), editions ara-nawawi and eng-nawawi, released into the public domain under the Unlicense. References and gradings are Imam an-Nawawi's own, as they appear in the text.