Sayyiduna Sufyan bin Abdullah Thaqafi (may Allah be pleased with him) said: I asked, "O Messenger of Allah! Tell me something about Islam such that I will not need to ask anyone else about it." He said: "Fear Allah and remain steadfast." I asked, "What else after that?" So he (peace and blessings be upon him) pointed towards his tongue (meaning: keep it under control and safeguard it).