1393. hadíth
قَالَ اَلصَّادِقُ عَلَيْهِ اَلسَّلاَمُ: فِي اَلرَّجُلِ يَبِيعُ اَلشَّيْءَ فَيَقُولُ اَلْمُشْتَرِي هُوَ بِكَذَا وَ كَذَا بِأَقَلَّ مِمَّا قَالَ اَلْبَائِعُ قَالَ "اَلْقَوْلُ قَوْلُ اَلْبَائِعِ إِذَا كَانَ اَلشَّيْءُ قَائِماً بِعَيْنِهِ مَعَ يَمِينِهِ ".
Imam Jafar ibn Muhammad Al-Sadiq (a.s) said regarding a man who sells something and the buyer claims that it was sold for a lower price than what the seller stated: "The statement of the seller is to be accepted if the item is still present in its original form, along with his oath."