(12) باب الْخَدِيعَةِ فِي الْبَيْعِ
It was narrated from Ibn 'Umar that:
a man told the Messenger of Allah that he was always being cheated. The Messenger of Allah said to him: "When you make a deal, say: There is no intention of cheating" So, whenever the man engages in a deal he says, 'There is no intention of cheating." "(Sahih )
Reference: Sunan an-Nasa'i 4484
In-book reference: Book 44, Hadith 36
English translation: Vol. 5, Book 44, Hadith 4489