What is the validity of a purchase when the instruction is 'Buy it for one hundred, but do not buy it for fifty'?
General Chapter
Al-Mughni
Book of Agency
Primary text
If the instruction is structured as, 'Buy it for one hundred, and do not buy it for fifty,' the agent is permitted to buy it for any amount exceeding fifty. Permission to buy for one hundred implicitly allows buying for less, but the explicit prohibition against buying for fifty removes only that specific amount. What remains above fifty still falls under the general permission implied by the authorization to purchase at one hundred.
Supporting text
There are two differing opinions regarding buying it for less than fifty in this scenario. The first opinion states it is permissible because the agent did not violate the explicit prohibition (against buying for fifty), similar to amounts exceeding fifty. The second opinion states it is not permissible, asserting that prohibiting the purchase for fifty serves as an explicit warning against any amount lower than fifty, just as authorizing the purchase for one hundred implies authorization for less, meaning the implied ruling is treated like an explicit prohibition.