Volume 8, Book 76, Number 485:
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.”