‏البيوع : Hadeeth No:3914 Abu Qatada al-Ansari (Allaah be pleased with him) reported he heard Allaah's Messenger (sallAllaahu alayhi wa sallam) say: Beware of swearing; it produces a ready sale for a commodity, but blots out the blessing....

‏الحج : Hadeeth No:3195 Abu Huraira reported Allaah's Messenger (sallAllaahu alayhi wa sallam) as saying: He who intends to do harm to its people (he meant Medina), Allaah would efface him as salt is dissolved in water. Ibn Hatim (one of the narrators) substituted the word" harm" for" mischief"....