It was narrated from Abu Hurairah that the Messenger of Allah P.B.U.H said: "There are three to whom Allah will not speak on the Day of Resurrection, nor 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 fledge to a ruler, only doing so Or the purpose of worldly gain, and if he is given something he fills it, but if he is not given anything he does not fulfill it." (Sahih)