Ibn Muskan narrated from Al-Halabi, from Abu Abdillah عليه السلام: Regarding a man who purchased a measured amount of food from another man, and then the seller said to the buyer, "Buy this other sack without measuring it, for it contains the same amount as the one you already purchased." Imam عليه السلام said: "This is not permissible unless it is measured." Imam عليه السلام further said: "Any food for which a specific measurement has been stipulated cannot be sold without measuring it. Such sales, based on estimation, are disapproved in the case of food."