Sahih Muslim
The Book Pertaining to Piety and Softening of Hearts (Kitab Al-Zuhd wa Al-Raqaiq)
Book Number: 042 / Hadith Number: 7121
Abu Huraira reported Allah's Messenger (may peace be upon him) as saying: The servant speaks words that he does not understand its repercussions but he sinks down in Hell-Fire farther than the distance between the east and the west.