If they intend by that a non-undivided amount, it is not valid for that reason. If they intend an undivided share of it, and they know the number of its cubits, it is valid. This is the opinion of al-Shafi'i. Abu Hanifa said: It is not valid, because 'cubit' is an expression for a specific plot of land, and its location is unknown. Our argument is that ten out of a hundred is one-tenth of it; if he said, 'I sold you a tenth of it,' it would be valid. Likewise, if he said, 'I sold you ten out of a hundred.' What they mentioned is not valid; rather, it is an expression for an amount, just as a measure (mikyal) is an expression for an amount. So, when he relates it to a whole, it becomes a part of it. If they agree that they intended an amount of it that is not undivided, the sale is not valid. If they do not know the cubits of the house, it is not valid because the whole is not known, and the parts of the land are different, so it is impossible for it to be specific or undivided. If he said, 'I sold you from the house from here to here,' it is permissible because it is known. If he said, 'ten cubits, its beginning is from here to here,' up to where the measurement ends, it is not valid, because the measurement varies and the location at which it ends is not known at the time of the contract. If he said, 'I sold you my share of this house,' and the amount of his share of it is not known, or he said, 'a share of it' or 'a portion,' it is not valid, because it is unknown. If they know that, it is valid. If he said, 'I sold you half of my house that adjoins your house,' it is not valid; he explicitly stated this because he does not know where it ends, so it is unknown.

Section: If he sells him one slave from two slaves or more, it is not valid. This is also the opinion of al-Shafi'i. Abu Hanifa said: If he sells him a slave from two or three on the condition of an option for him, it is valid because