Malik related to me from Abdullah ibn Dinar that Abu Salih as-Samman informed him that Abu Hurayra said, "Truly a man utters wordsto which he attaches no importance, and by them he falls into the fireof Jahannam, and truly a man utters words to which he attaches noimportance, and by them Allah raises him into the Garden."
USC-MSA web (English) reference: Book 56, Hadith 6
Arabic reference: Book 56, Hadith 1819