Who begins the oath when the buyer and seller disagree on the price while the commodity is still extant?
Chapter on Selling the Musarrah (Animal with milk retained in udder)
Al-Mughni
Book of Sales
Primary text
If the buyer and seller disagree on the price while the commodity remains intact—the seller claiming twenty and the buyer ten—the ruling is determined by evidence (*bayyinah*). If neither has evidence, they engage in mutual swearing (*taḥāluf*). This is the position of Shuʻrayḥ, Abu Ḥanīfah, al-Shāfiʻī, and one narration from Mālik. The initial oath is taken by the seller, who swears that he sold it for the higher amount claimed. If the buyer accepts this sworn statement, the sale proceeds at that price. If the buyer refuses, he also swears to his claimed lower price. This precedence for the seller is derived from the tradition stating, 'The ruling follows what the seller says, or they both rescind the sale.' Furthermore, the seller has the stronger position because if they both swear, the commodity returns to him, similar to the possessor of the item (*ṣāḥib al-yad*).
Supporting text
A dissenting view holds that the buyer's word is taken with his oath, as the seller is claiming an additional ten, which the buyer denies, and the claimant's word is accepted against the denier. This view is held by Abu Thawr and Zufar. Al-Shaʻbī stated that the ruling is either with the seller or they rescind the sale, which is also narrated as the primary view from Ahmad.