Sahih Bukhari Volume 3, Book 48, Hadith Number 838.

Narated By Abu Huraira : Allah’s Apostle 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 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.
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.”