“I said: ‘O Messenger of Allah, tell me of something that I can adhere to.’ He said: ‘Say: “Allah is my Lord,” then stand straight (adhere steadfastly to Islam).’ He said: ‘O Messenger of Allah, what is the thing that you fear most for me?’ The Messenger of Allah (ﷺ) took hold of his own tongue, then he said: ‘This.’”
Sunan Ibn Majah Book 36, Hadith 47
← Previous Hadith “Whoever believes in Allah and the Last Day, let him say something good, or else remain silent.”

Sunan Ibn Majah Book 36, Hadith 46 Next Hadith → “I was with the Messenger of Allah (ﷺ) on a journey. One morning I drew close to him when we were on the move and said: ‘O Messenger of Allah, tell me of an action that will gain me admittance to Paradise and keep me far away from Hell.’ He said: ‘You have asked for something great, but it is easy for the one for whom Allah makes it easy. Worship Allah and do not associate anything in worship with Him, establish prayer, pay charity, fast Ramadan, and perform Hajj to the House.’ Then he said: ‘Shall I not tell you of the means of goodness? Fasting is a shield, and charity extinguishes sin as water extinguishes fire, and a man’s prayer in the middle of the night.’ Then he recited: “Their sides forsake their beds” until he reached: “As a reward for what they used to do.” Then he said: ‘Shall I not tell you of the head of the matter, and its pillar and pinnacle? (It is) Jihad.’ Then he said: ‘Shall I not tell you of the basis of all that?’ I said: ‘Yes.’ He took hold of his tongue then said: ‘Restrain this.’ I said: ‘O Prophet of Allah, will we be brought to account for what we say?’ He said: ‘May your mother not found you, O Mu’adh! Are people thrown onto their faces in Hell for anything other than the harvest of their tongues?’”

Sunan Ibn Majah Book 36, Hadith 48