Sunan an-Nasa'i, Hadith 4294 ⓘ
It was narrated that Waqi bin Khadij said: "The Messenger of Allah said: 'The worst of earnings arte the gift of a female fornicator, the price of a dog and the earnings of a cupper.""
أَخْبَرَنَا شُعَيْبُ بْنُ يُوسُفَ، عَنْ يَحْيَى، عَنْ مُحَمَّدِ بْنِ يُوسُفَ، عَنِ السَّائِبِ بْنِ يَزِيدَ، عَنْ رَافِعِ بْنِ خَدِيجٍ، قَالَ قَالَ رَسُولُ اللَّهِ صلى الله عليه وسلم " شَرُّ الْكَسْبِ مَهْرُ الْبَغِيِّ وَثَمَنُ الْكَلْبِ وَكَسْبُ الْحَجَّامِ " .
also referenced under: Book 42, Hadith 32 (In-Book) & Volume 5, Book 42, Hadith 4299 (DarusSalam)