"The Messenger of Allah said: 'The two parties to a transaction have the choice so long as they have not separated. If they are honest and open, their transaction will be blessed, but if they tell lies and conceal anything, the blessing of their transaction will be lost."  

قَالَ رَسُولُ اللَّهِ ﷺ الْبَيِّعَانِ بِالْخِيَارِ مَا لَمْ يَفْتَرِقَا فَإِنْ صَدَقَا وَبَيَّنَا بُورِكَ فِي بَيْعِهِمَا وَإِنْ كَذَبَا وَكَتَمَا مُحِقَ بَرَكَةُ بَيْعِهِمَا