Musannaf Ibn Abi Shaybah

Hazrat Salm says that I asked Hazrat Muhammad bin Sirin about a person who sold goods to another person for two months, and placed the condition on the buyer that if he sold it before two months, he would have to pay the price in cash? He replied, "I do not see any harm in this."

Ibrahim says that if a man buys a house and then the buyer says to the seller, "Whenever I come to you with its money, it will be returned to you," then this condition will be invalid and the sale will become binding.

Ibrahim says that in a sale, any condition that is contrary to the sale, the sale nullifies that condition.