‏البيوع : Hadeeth No:3805 Rafi b. Khadij (Allaah be pleased with him) reported: I heard Allaah's Prophet (sallAllaahu alayhi wa sallam) as saying: The worst earning is the earning of a prostitute, the price of a dog and the earning of a cupper....

‏الجهاد والسير‏ : Hadeeth No:4391 This hadith has been narrated on the authority of Bara' with another chain of transmitters, but this hadith is short as compared with other ahadith which are more detailed....