What did Allah (swt) reveal concerning those who break their oaths when trying to purchase goods in a dishonest manner as mentioned in the hadith narrated by `Abdullah bin Abu `Aufa about Prophet Muhammad (saw)?
 Narrated `Abdullah bin Abu `Aufa:                     A man displayed some goods in the market and swore by Allah that he had been offered so much for that, that which was not offered, and he said so, so as to cheat a Muslim. On that occasion the following Verse was revealed: "Verily! Those who purchase a small gain at the cost of Allah's covenant and their oaths (They shall have no portion in the Hereafter ..etc.)' (3.77)