The Messenger of Allah ﷺ forbade muzabanah. Muzabanah is the sale of fresh dates on the tree for dried dates by measure, and the sale of grapes on the vine for raisins by measure.
أن رسول الله ﷺ نهي عن المزابنة. والمزابنة بيع الثمر بالتمر كيلا، وبيع الكرم بالزبيب كيلا.
Malik narrated it in "Sales" (23) from Nafi, from Abdullah bin Umar, mentioning it. Bukhari narrated it in "Sales" (2185), and Muslim in "Sales" (1542), both through the route of Malik, similarly. Muslim also narrated it through another route from Ubaydullah, from Nafi, from Abdullah bin Umar, who said, "The Messenger of Allah ﷺ forbade muzabanah. Muzabanah is selling the fruit on the palm trees for dried dates by measure, and selling raisins for grapes by measure, and applying estimation to every kind of fruit." Ayub also narrated it from Nafi, from Ibn Umar, that the Messenger of Allah ﷺ forbade muzabanah. Muzabanah is when what is on the tops of the palm trees is sold for a specified measure of dried dates, so that if it turns out more, it belongs to the buyer, and if less, it is still owed by him.Tirmidhi narrated it (1300) through the route of Muhammad bin Ishaq, from Nafi, from Ibn Umar, from Zayd bin Thabit, that the Prophet ﷺ forbade muhaqalah and muzabanah, except that he permitted the people of araya to sell their share for an equivalent estimated measure. Tirmidhi said, "This is how Muhammad bin Ishaq narrated the hadith of Zayd bin Thabit. But Ayub, Ubaydullah bin Umar, and Malik bin Anas narrated it from Nafi, from Ibn Umar, that the Prophet ﷺ forbade muhaqalah and muzabanah." And with this same chain, from Ibn Umar, from Zayd bin Thabit, from the Prophet ﷺ, that he permitted araya. This is more sahih than the hadith of Muhammad bin Ishaq. End of quote.What Tirmidhi means is that Ibn Ishaq made a mistake, merging one hadith into another. What Ibn Umar actually narrated from Zayd bin Thabit was only the exception concerning araya, as will be explained later. As for the prohibition of muzabanah, he narrated it from the Prophet ﷺ without the intermediary of Zayd bin Thabit, so Muhammad bin Ishaq differed here from Ayub, Ubaydullah bin Umar, and Malik.As for the explanation of muzabanah, its apparent sense is that it is a raised report, since it is a legal term that was not known before Islam, so it is more likely correct that its explanation came from the Prophet ﷺ. However, Imam Ahmad narrated it (5320) from Abdul-Wahhab bin Abdul-Majid, from Ayub, from Nafi, from Ibn Umar, that the Prophet ﷺ forbade muzabanah. He said, Nafi used to explain it as selling fruit for an estimated measure of dried dates by a specified measure, so that if it turns out more, it belongs to the buyer, and if less, it is still owed by him. This suggests that the explanation came from Nafi, though the correct view is the former, and perhaps Nafi only intended to confirm this transmitted explanation, not that he devised it himself.Imam Ahmad also narrated it (4490) from Ismail (that is, Ibn Ulaya), from Ayub, similarly to the narration of Muslim and others, indicating that the explanation came from the Prophet ﷺ. A similar report will also come from Abu Saeed Khudri. Ibn Hajar likewise held the view that the explanation is a raised report attributed to the Prophet ﷺ.His saying, "muzabanah," is a mutual-action form from zabn, with fatha on the zay and sukun on the ba, meaning strong pushing away. From this, war is called "zabun" because of the intensity of pushing in it. This particular type of sale was called muzabanah because each of the two parties pushes the other away from his right.The established practice among the majority of scholars is that muzabanah and muhaqalah are invalid. This is the view held by Malik, Uzai, Shafii, Ahmad, Ishaq bin Rahwayh, and others.