‏البيوع : Hadeeth No:3615 'Abdullah (b. 'Umar) (Allaah be pleased with him) said that Allaah's Messenger (sallAllaahu alayhi wa sallam) forbade the transaction called habal al-habala....

‏الجهاد والسير‏ : Hadeeth No:4307 It has been narrated on the authority of Abdullah that the Messenger of Allaah (sallAllaahu alayhi wa sallam) said: There will be for every perfidious person on the Day of Judgment a flag by which he will be recognised. It will be announced: Here is the breach of faith of so and so....