Is it permissible for sellers to stipulate the purchase of a large quantity of yogurt along with milk, despite their knowledge that this burdens the buyers and that they have no other solution to provide the essential milk for their children?

Firstly: It is not permissible for a milk seller to stipulate the purchase of yogurt along with it, due to the harm and damage inflicted upon people. The sin falls upon the seller. He should raise the price of milk to achieve his profit without harming people, and the state should monitor this.

Secondly: The sale is valid because stipulating one contract within another is permissible according to the preponderant opinion, as long as it does not lead to usury, contrary to the majority of scholars who consider it to invalidate the sale and categorize it under "two sales in one sale." The Malikis and Ahmad, in one narration, have gone to the permissibility of this, and it was chosen by Sheikh al-Islam Ibn Taymiyyah and many contemporary scholars, on the condition that it is not a loan that brings benefit or a trick to usury.