Sufyan bin Abdullah Thaqafi (may Allah be pleased with him) narrates: He said, "O Messenger of Allah (peace be upon him)! Tell me about something which I may hold firmly." The Prophet (peace be upon him) said: "Say, 'My Lord is Allah,' and then remain steadfast upon it." He said, "O Messenger of Allah (peace be upon him)! Of what do you fear most concerning me?" The Prophet (peace be upon him) pointed towards his tongue and said this.