‏الزهد والرقائق‏ : Hadeeth No:7122 Shaqiq reported that it was said to Usama b. Zaid: Why don't you visit 'Uthman and talk to him? Thereupon he said: Do you think that I have not talked to him but that I have made you hear? By Allaah. I have talked to him (about things) concerning me and him and I did not like to divulge those things...

‏البيوع : Hadeeth No:3907 Ibn 'Abbas (Allaah be pleased with them) reported that when Allaah's Messenger (sallAllaahu alayhi wa sallam) came to (Medina) and the people were paying in advance (for the fruits, etc.), he said to them: He who makes an advance payment should not make advance payment except for a specified measure...