قَالَ مَالِك : وَمَنْ سَلَّفَ فِي شَيْءٍ مِنَ الْحَيَوَانِ إِلَى أَجَلٍ مُسَمًّى فَوَصَفَهُ وَحَلَّاهُ وَنَقَدَ ثَمَنَهُ، فَذَلِكَ جَائِزٌ، وَهُوَ لَازِمٌ لِلْبَائِعِ وَالْمُبْتَاعِ عَلَى مَا وَصَفَا وَحَلَّيَا، وَلَمْ يَزَلْ ذَلِكَ مِنْ عَمَلِ النَّاسِ الْجَائِزِ بَيْنَهُمْ وَالَّذِي لَمْ يَزَلْ عَلَيْهِ أَهْلُ الْعِلْمِ بِبَلَدِنَا
Imam Malik, may Allah have mercy on him, said that it is permissible to do salam (advance payment sale) in animals when the term is specified, and the characteristics and appearance of the animal are described, and the price is paid. Then the seller must deliver an animal of the same kind, and the buyer must accept it. The people of our city have always practiced this and have always held this view.