It is narrated from Sayyiduna Abu Umamah (may Allah be pleased with him) that a man said: "O Messenger of Allah, what is faith?" He (peace and blessings be upon him) said: "When your good deed pleases you and your bad deed grieves you, then you are a believer."
Hadith Referenceالمعجم الكبير للطبراني / باب الصاد / 7509