قَالَ مَالِك فِي رَجُلٍ قَالَ لِرَجُلٍ : أَشْتَرِي مِنْكَ هَذِهِ الْعَجْوَةَ خَمْسَةَ عَشَرَ صَاعًا أَوِ الصَّيْحَانِيَّ عَشَرَةَ أَصْوُعٍ، أَوِ الْحِنْطَةَ الْمَحْمُولَةَ خَمْسَةَ عَشَرَ صَاعًا أَوِ الشَّامِيَّةَ عَشَرَةَ أَصْوُعٍ بِدِينَارٍ، قَدْ وَجَبَتْ لِي إِحْدَاهُمَا : إِنَّ ذَلِكَ مَكْرُوهٌ لَا يَحِلُّ، وَذَلِكَ أَنَّهُ قَدْ أَوْجَبَ لَهُ عَشَرَةَ أَصْوُعٍ صَيْحَانِيًّا، فَهُوَ يَدَعُهَا وَيَأْخُذُ خَمْسَةَ عَشَرَ صَاعًا مِنَ الْعَجْوَةِ، أَوْ تَجِبُ عَلَيْهِ خَمْسَةَ عَشَرَ صَاعًا مِنَ الْحِنْطَةِ الْمَحْمُولَةِ فَيَدَعُهَا وَيَأْخُذُ عَشَرَةَ أَصْوُعٍ مِنَ الشَّامِيَّةِ، فَهَذَا أَيْضًا مَكْرُوهٌ لَا يَحِلُّ، وَهُوَ أَيْضًا يُشْبِهُ مَا نُهِيَ عَنْهُ مِنْ بَيْعَتَيْنِ فِي بَيْعَةٍ، وَهُوَ أَيْضًا مِمَّا نُهِيَ عَنْهُ أَنْ يُبَاعَ مِنْ صِنْفٍ وَاحِدٍ مِنَ الطَّعَامِ اثْنَانِ بِوَاحِدٍ
Imam Malik, may Allah have mercy on him, said that if the buyer says to the seller: I have bought from you fifteen sa’ of this type of dates or ten sa’ of this type for one dinar, I will definitely take one of the two. Or he says: I have bought from you fifteen sa’ of this type of wheat or ten sa’ of this type of wheat for one dinar, I will definitely take one of the two, then this is not correct. It is as if he took ten sa’ of dates and then left them and took fifteen sa’ of dates, or left ten sa’ of wheat and took fifteen sa’ in exchange. This is also included in it, that is, making two sales in one sale.