Mishkat al-Masabih 11 Business Transactions كتاب البيوع 41

وَعَن حَكِيم بن حزَام قَالَ: قَالَ رَسُولُ اللَّهِ صَلَّى اللَّهُ عَلَيْهِ وَسَلَّمَ: «الْبَيِّعَانِ بِالْخِيَارِ مَا لَمْ يَتَفَرَّقَا فَإِنْ صَدَقَا وَبَيَّنَا بُوِرَكَ لَهُمَا فِي بَيْعِهِمَا وَإِنْ كَتَمَا وَكَذَبَا مُحِقَتْ بَرَكَةُ بَيْعِهِمَا»

Hakim b. Hizam reported God’s Messenger as saying, “Both parties in a business transaction have a right to annul it so long as they have not separated ; and if they tell the truth and make everything clear they will be blessed in their transaction, but if they conceal anything and lie the blessing on their transaction will be blotted out.” (Bukhari and Muslim.)