Sahih Bukhari Volume 008, Book 076, Hadith Number 504.
Narated By Hudhaifa : Allah's Apostle narrated to us two narrations, one of which I have seen (happening) and I am waiting for the other. He narrated that honesty was preserved in the roots of the hearts of men (in the beginning) and then they learnt it (honesty) from the Qur'an, and then they learnt it from the (Prophet's) Sunna (tradition). He also told us about its disappearance, saying, "A man will go to sleep whereupon honesty will be taken away from his heart, and only its trace will remain, resembling the traces of fire. He then will sleep whereupon the remainder of the honesty will also be taken away (from his heart) and its trace will resemble a blister which is raised over the surface of skin, when an ember touches one's foot; and in fact, this blister does not contain anything. So there will come a day when people will deal in business with each other but there will hardly be any trustworthy persons among them. Then it will be said that in such-and-such a tribe there is such-and-such person who is honest, and a man will be admired for his intelligence, good manners and strength, though indeed he will not have belief equal to a mustard seed in his heart." The narrator added: There came upon me a time when I did not mind dealing with anyone of you, for if he was a Muslim, his religion would prevent him from cheating; and if he was a Christian, his Muslim ruler would prevent him from cheating; but today I cannot deal except with so-and-so and so-and-so. (See Hadith No. 208, Vol. 9)