Hadith:
Once, Mu’adh ibn Jabal (r.a.) asked the Prophet (sallellahu alaihi wa sallam) to inform him of some good work that would admit him into Paradise and distance him from the Hellfire.
The Prophet (s.a.w.s.) mentioned to him the virtues of many good deeds, then said:
“Shall I inform you of the foundation of all of that?”
Mu`adh (r.a.) said: “Certainly.”
The Prophet (s.a.w.s.) took hold of his tongue and said: “Restrain yourself from this.”
Mu’adh (r.a.) then asked: “O Prophet of Allah! Are we held to task for the things that we say?”
The Prophet (s.a.w.s.) replied:”May your mother be bereaved of you, O Mu’adh! Does anything topple people headlong into the Hellfire save the harvests of their tongues?”
[“Sunan al-Tirmidhi” and “Sunan Ibn Majah”]