قَالَ مَالِك فِي رَجُلٍ ابْتَاعَ سِلْعَةً مِنْ رَجُلٍ بِعَشَرَةِ دَنَانِيرَ نَقْدًا أَوْ بِخَمْسَةَ عَشَرَ دِينَارًا إِلَى أَجَلٍ، قَدْ وَجَبَتْ لِلْمُشْتَرِي بِأَحَدِ الثَّمَنَيْنِ : إِنَّهُ لَا يَنْبَغِي ذَلِكَ، لِأَنَّهُ إِنْ أَخَّرَ الْعَشَرَةَ كَانَتْ خَمْسَةَ عَشَرَ إِلَى أَجَلٍ، وَإِنْ نَقَدَ الْعَشَرَةَ كَانَ إِنَّمَا اشْتَرَى بِهَا الْخَمْسَةَ عَشَرَ الَّتِي إِلَى أَجَلٍ .
Imam Malik, may Allah have mercy on him, said that if a person buys a cloth on the condition that if he pays cash, he should pay ten dinars, and if he pays on credit, he should pay fifteen dinars, in any case, the buyer must pay one of the two prices, then this is not permissible, because if he does not pay ten dinars in cash, then fifteen on credit are in place of ten, and if he pays ten in cash, then it is as if he has taken fifteen on credit in exchange for it.