قَالَ مَالِك : وَالدَّلِيلُ عَلَى الدَّيْنِ يَغِيبُ أَعْوَامًا ثُمَّ يُقْتَضَى فَلَا يَكُونُ فِيهِ إِلَّا زَكَاةٌ وَاحِدَةٌ ، أَنَّ الْعُرُوضَ تَكُونُ عِنْدَ الرَّجُلِ لِلتِّجَارَةِ أَعْوَامًا ثُمَّ يَبِيعُهَا فَلَيْسَ عَلَيْهِ فِي أَثْمَانِهَا إِلَّا زَكَاةٌ وَاحِدَةٌ ، وَذَلِكَ أَنَّهُ لَيْسَ عَلَى صَاحِبِ الدَّيْنِ أَوِ الْعُرُوضِ أَنْ يُخْرِجَ زَكَاةَ ذَلِكَ الدَّيْنِ أَوِ الْعُرُوضِ مِنْ مَالٍ سِوَاهُ ، وَإِنَّمَا يُخْرِجُ زَكَاةَ كُلِّ شَيْءٍ مِنْهُ ، وَلَا يُخْرِجُ الزَّكَاةَ مِنْ شَيْءٍ عَنْ شَيْءٍ غَيْرِهِ
Imam Malik, may Allah have mercy on him, said: What we have stated, that a debt is not collected for several years, and then when it is collected, only one year's zakat becomes obligatory, the evidence for this is that a person has trade goods with him for years, and when he sells them, only one zakat is obligatory on the price he receives. This is because it is not obligatory upon the owner of the debt or the owner of the wealth to pay zakat for this wealth or debt from another wealth; rather, zakat for each wealth should be paid from that very wealth, and not that zakat for one thing be given from another thing.