Sunan Ibn Majah, Book 37, Hadith 4387 (In-Book) ⓘ
It was narrated that Abu Hurairah said: “The Prophet was asked: ‘What most admits people to Paradise?’ He said: ‘Piety and good manners.’ And he was asked: ‘What most leads people to Hell?’ He said: ‘The two hollow ones: The mouth and the private part.’”
حَدَّثَنَا هَارُونُ بْنُ إِسْحَاقَ، وَعَبْدُ اللَّهِ بْنُ سَعِيدٍ، قَالاَ حَدَّثَنَا عَبْدُ اللَّهِ بْنُ إِدْرِيسَ، عَنْ أَبِيهِ، وَعَمِّهِ، عَنْ جَدِّهِ، عَنْ أَبِي هُرَيْرَةَ، قَالَ : سُئِلَ النَّبِيُّ ـ صلى الله عليه وسلم ـ : مَا أَكْثَرُ مَا يُدْخِلُ الْجَنَّةَ قَالَ : " التَّقْوَى وَحُسْنُ الْخُلُقِ " . وَسُئِلَ : مَا أَكْثَرُ مَا يُدْخِلُ النَّارَ قَالَ : " الأَجْوَفَانِ : الْفَمُ وَالْفَرْجُ " .
also referenced under: Hadith 4246 (Reference) & Volume 5, Book 37, Hadith 4246 (DarusSalam)