ذِكْرُ الزَّجْرِ عَنْ بَيْعِ الْجِنْسِ مِنَ الطَّعَامِ بِجِنْسِهِ إِلَّا مِثْلًا بِمِثْلٍ
[Machine] Buy it and then buy barley with it. The boy went and took a measure and some additional barley. When Ma'mar came, the boy informed him about that. Ma'mar asked him, "Why did you do that?" Go and return it, and do not take anything unless it is like for like. For I used to hear the Messenger of Allah ﷺ saying, 'Food should be exchanged like for like, and our food in those days was barley.'"
بِعْهُ ثُمَّ اشْتَرِ بِهِ شَعِيرًا فَذَهَبَ الْغُلَامُ وَأَخَذَ صَاعًا وَزِيَادَةَ بَعْضِ صَاعٍ فَلَمَّا جَاءَ مَعْمَرٌ أَخْبَرَهُ بِذَلِكَ فَقَالَ لَهُ مَعْمَرٌ لِمَ فَعَلْتَ ذَلِكَ انْطَلَقَ فَرُدَّهُ وَلَا تَأْخُذْ إِلَّا مِثْلًا بِمِثْلٍ فَإِنِّي كُنْتُ أَسْمَعُ رَسُولَ اللَّهِ ﷺ يَقُولُ «الطَّعَامُ بِالطَّعَامِ مِثْلًا بِمِثْلٍ وَكَانَ طَعَامُنَا يَوْمَئِذٍ الشَّعِيرَ»