Narrated Abu Huraira: That he heard Allah's Apostle saying, "A slave of Allah may utter a word without thinking whether it is right or wrong, he may slip down in the Fire as far away a distance equal to that between the east."

Narrated Abu Huraira: The Prophet; said, "A slave (of Allah) may utter a word which pleases Allah without giving it much importance, and because of that Allah will raise him to degrees (of reward): a slave (of Allah) may utter a word (carelessly) which displeases Allah without thinking of its gravity and because of that he will be thrown into the Hell-Fire."

Narrated Sahl bin Sa`d: The Prophet said, "Whoever guarantees me (the chastity of) what is between his legs (i.e. his private parts), and what is between his jaws (i.e., his tongue), I guarantee him Paradise."