Sunan Ibn Majah, Chapter: The Chapters on Jihad

that the Messenger of Allah (saw) said: "There are three to whom Allah will not speak on the Day of Resurrection, not will He look at them nor purify them, and theirs will be a painful torment: A man who has surplus water in the desert and withholds it from a wayfarer; a man who sells a man his product after 'Asr, swearing by Allah that he bought it for such and such a price, and the other believes him, but that is not the case; and a man who gives his pledge to a ruler, only doing to for the purpose of worldly gain, and if he is given something he fulfills it, but if he is not given anything he does not fulfill it."