The Messenger of Allah ﷺ said, "Whoever guarantees for me what is between his jaws and what is between his legs, I will guarantee him Paradise."
حدثنا محمد بن عبد الأعلى الصنعاني حدثنا عمر بن علي المقدمي عن أبي حازم
قال رسول الله ﷺ من يتكفل لي ما بين لحييه وما بين رجليه أتكفل له بالجنة
Bukhari also reported it in the Book of Heart-Softening Matters, Chapter on Guarding the Tongue, hadith no. 6474, through Umar bin Ali Muqaddami with the same chain. On this subject there is also a narration from Abu Hurairah [to come at 2409] and Ibn Abbas [perhaps referring to the hadith in Bazzar (Kashf Astar), 2/391, no. 1926].