Narrated Abu Huraira:Allah's Apostle said, "There are three persons whom Allah will not look at on the Day of Resurrection, nor will he purify them and theirs shall be a severe punishment. They are:
1. A man possessed superfluous water, on a way and he withheld it from travelers.
2. A man who gave a pledge of allegiance to a ruler and he gave it only for worldly benefits. If the ruler gives him something he gets satisfied, and if the ruler withholds something from him, he gets dissatisfied.
3. And man displayed his goods for sale after the 'Asr prayer and he said, 'By Allah, except Whom None has the right to be worshipped, I have been given so much for my goods,' and somebody believes him (and buys them)."
The Prophet then recited: "Verily! Those who purchase a little gain at the cost of Allah's Covenant and their oaths." (3.77)