‏النكاح : Hadeeth No:3286 Ibn Umar (Allaah be pleased with them) reported Allaah's Prophet (sallAllaahu alayhi wa sallam) as having said this: None amongst you should outbid another in a transaction, nor should he make proposals of marriage upon the proposal made by someone else....

‏السلام : Hadeeth No:5419 Ibn Umar reported Allaah's Messenger (sallAllaahu alayhi wa sallam) as saying: When there are three (persons), two should not converse secretly between themselves to the exclusion of the (third) one....