Sahih Muslim Book 33, Hadith Number 6408.

Chapter : The growth of a child in the womb of a mother and his destiny in regard to his livelihood, his deeds. both good and evil.

Sahl b. Sa’d reported it from Allah’s Messenger (may peace be upon him) that a person performs deeds like the deeds of the people of Paradise apparently before people and he would be amongst the dwellers of Hell and a person acts apparently like the people of Hell, but (in fact) he would be among the dwellers of Paradise.