‏البيوع : Hadeeth No:3653 Jabir b. Abdullah (Allaah be pleased with them) reported Allaah's Messenger (sallAllaahu alayhi wa sallam) as saying: When you purchase foodgrains, do not sell them until you have taken possession of them....

‏البر والصلة والآداب‏ : Hadeeth No:6305 This hadith has been transmitted on the authority of Zuhri with a slight variation of wording....