Sahih Bukhari, Chapter: Witnesses

Allah's Apostle (SAW) said, "There are three persons whom Allah will neither talk to nor look at, nor purify from (the sins), and they will have a painful punishment. (They are): (1) A man possessed superfluous water on a way and he withheld it from the travelers. (2) a man who gives a Baia (pledge of allegiance) to a Muslim ruler and gives it only for worldly gains. If the ruler gives him what he wants, he remains obedient to it, otherwise he does not abide by it, and (3) a man bargains with another man after the Asr prayer and the latter takes a false oath in the Name of Allah claiming that he has been offered so much for the thing and the former (believes him and) buys it."