"When two people meet to engage in trade the transaction between them is not binding until they separate, unless they have chosen to conclude the transaction."
أَنَّهُ سَمِعَ رَسُولَ اللَّهِ ﷺ يَقُولُ كُلُّ بَيِّعَيْنِ لاَ بَيْعَ بَيْنَهُمَا حَتَّى يَتَفَرَّقَا إِلاَّ بَيْعَ الْخِيَارِ