حَدَّثَنَا قُتَيْبَةُ بْنُ سَعِيدٍ، حَدَّثَنَا يَعْقُوبُ، - يَعْنِي ابْنَ عَبْدِ الرَّحْمَنِ الْقَارِيَّ - عَنْ أَبِي حَازِمٍ، عَنْ سَهْلِ بْنِ سَعْدٍ السَّاعِدِيِّ، أَنَّ رَسُولَ اللَّهِ صلى الله عليه وسلم قَالَ ‏"‏ إِنَّ الرَّجُلَ لَيَعْمَلُ عَمَلَ أَهْلِ الْجَنَّةِ فِيمَا يَبْدُو لِلنَّاسِ وَهُوَ مِنْ أَهْلِ النَّارِ ‏.‏ وَإِنَّ الرَّجُلَ لَيَعْمَلُ عَمَلَ أَهْلِ النَّارِ فِيمَا يَبْدُو لِلنَّاسِ وَهُوَ مِنْ أَهْلِ الْجَنَّةِ ‏"‏ ‏.‏

Sahl b. Sa'd reported it from Allah's Messenger (PBUH) 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. Translation Not Available

Book reference: Sahih Muslim Book 46 Hadith 6408
Web reference: Sahih Muslim Book 33 Hadith 112 b