The Messenger of Allah ﷺ was asked what most often admits people into Paradise. He replied, "Mindfulness of Allah and good character."He was then asked what most often casts people into Hell. He replied, "The mouth and the private parts."
قال سئل رسول الله ﷺ عن أكثر ما يدخل الناس الجنة؟ فقال: تقوى الله وحسن الخلق. وسئل عن أكثر ما يدخل الناس النار؟ فقال: الفم والفرج
Narrated by Tirmidhi (2004), Ibn Hibban (476), and Hakim (4/324), all through the route of Abdullah bin Idris, who said, "My father told me, from my grandfather, from Abu Hurairah," and so on.Its chain of transmission is hasan because of Abdullah's grandfather, who is Yazid bin Abdul-Rahman Awdi, for he is hasan al-hadith. Tirmidhi said, "This is a sahih, unusual hadith." Hakim said, "This is a hadith with a sahih chain."Ahmad narrated it (7907) through another route, from Dawud bin Yazid, from his father, with the same wording. Dawud bin Yazid is the uncle of Abdullah bin Idris, and he is daif, but he has corroboration.Ibn Majah narrated it (4246) through the route of Abdullah bin Idris, from his father and his uncle together, combining the father and the uncle.