“The Prophet used to give us dates from the collection (mixed) [1] dates, and we would exchange them for dates that were better, and we add to the price. [2] The Messenger of Allah said: ‘It is not right to give one Sa of dates for two Sa, nor one Dirham for two Dirham. A Dirham for a Dirham and a Dinar for a Dinar is allowed: the only difference between them is in weight (i.e., the weight must be equal.)’” Sahih  

كَانَ النَّبِيُّ ﷺ يَرْزُقُنَا تَمْرًا مِنْ تَمْرِ الْجَمْعِ فَنَسْتَبْدِلُ بِهِ تَمْرًا هُوَ أَطْيَبُ مِنْهُ وَنَزِيدُ فِي السِّعْرِ فَقَالَ رَسُولُ اللَّهِ ﷺ لاَ يَصْلُحُ صَاعُ تَمْرٍ بِصَاعَيْنِ وَلاَ دِرْهَمٌ بِدِرْهَمَيْنِ وَالدِّرْهَمُ بِالدِّرْهَمِ وَالدِّينَارُ بِالدِّينَارِ لاَ فَضْلَ بَيْنَهُمَا إِلاَّ وَزْنًا