takes all the walnuts based on that standard, he said: It is not permissible. And regarding a man who buys loads of grain by measure, and says to the seller: "Measure one load for me and I will take the rest based on this measure," he said: I dislike this until he measures all of them. Ath-Thawri said: Our companions used to dislike this, because the contents of the loads differ; there may be more in some than in others, so what is in some cannot be known by measuring others. Walnuts vary in number, so there may be more in one basket than another, thus their estimation by volume is not valid, just as it is not valid to estimate what is measured by volume using weight, nor what is weighed using volume.

738 - Issue: He said: (If he buys a heap (subrah) on the condition that every measure (makil) of it is for a known price, it is permissible.)

To summarize this, if he says: "I sold you this heap, every qafiz of it for a dirham," it is valid, even if they do not know the amount of it at the time of the contract. This is the view of Malik, al-Shafi'i, Abu Yusuf, and Muhammad. Abu Hanifah said: It is valid for one qafiz and void for the rest, because the total price is unknown, so it is invalid like selling purchased goods by their marked price. Our evidence is that the object sold is known by sight, and the price is known by his reference to what its total amount is determined by a means not dependent on the contracting parties, which is that the heap is measured and the price is distributed according to the number of its qafizes, thus its total is known; therefore, it is permissible, just as if he sold what his capital for it was seventy-two by way of murabahah, for every thirteen dirhams one dirham, for it is not known at the moment, but is known by calculation; thus it is here. Furthermore, because the item sold is known by sight, and the price is known for the amount corresponding to every part of the item sold, it is therefore valid, like the aforementioned principle. It has been narrated from Ali, may Allah be pleased with him, that he hired himself out for every bucket for a date, and he came to the Prophet (may Allah's peace and blessings be upon him) with the dates.