Hadith 3 – Guarding the Tongue
إِنَّ الْعَبْدَ لَيَتَكَلَّمُ بِالْكَلِمَةِ مَا يَتَبَيَّنُ فِيهَا، يَزِلُّ بِهَا فِي النَّارِ أَبْعَدَ مِمَّا بَيْنَ الْمَشْرِقِ وَ الْمَغْرِبِ A slave [of Allah] may utter a word without giving it much thought by which he slips into the fire a distance further than that between east and west. (Bukhari and Muslim)