Yahya related to me from Malik from Abdullah ibn Dinar from Abdullah ibn Umar that a man mentioned to the Messenger of Allah ﷺ that he was always being cheated in business transactions. The Messenger of Allah ﷺ said, "When you enter a transaction, say, 'No trickery.' So whenever that man entered a transaction, he would say, 'No trickery.' "

حَدَّثَنِي يَحْيَى، عَنْ مَالِكٍ، عَنْ عَبْدِ اللَّهِ بْنِ دِينَارٍ، عَنْ عَبْدِ اللَّهِ بْنِ عُمَرَ، أَنَّ رَجُلاً، ذَكَرَ لِرَسُولِ اللَّهِ ﷺ أَنَّهُ يُخْدَعُ فِي الْبُيُوعِ فَقَالَ رَسُولُ اللَّهِ ﷺ " إِذَا بَايَعْتَ فَقُلْ لاَ خِلاَبَةَ " . قَالَ فَكَانَ الرَّجُلُ إِذَا بَايَعَ يَقُولُ لاَ خِلاَبَةَ .