Hadith 46:19
Sahl b. Sa'd reported it from Allah's Messenger (ﷺ) 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.
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 "
Original Reference: Sahih Muslim 112 b