If the sale is valid and the condition is void, then how can the sale be valid despite the condition being void?

The basis for the validity of some contracts and the invalidity of their conditions is the story of Barirah, in which the Prophet, peace and blessings be upon him, invalidated the condition of wala' (loyalty/patronage) for the seller while upholding the contract itself. Scholars have agreed that in this case, the sale is valid and the condition is void.

Some jurists generalized this ruling, holding that any condition that contradicts the essence of the sale renders the condition void while the sale remains valid, such as stipulating no loss, or that the sold item not be resold or gifted.

However, some jurists restricted the ruling of the sale's validity and the condition's invalidity to conditions that are neither required by the contract nor contradictory to it. They categorized conditions in a sale into four types: those that invalidate both the sale and the condition, those that validate the sale but invalidate the condition, those that validate both the sale and the condition, and a condition that must be mentioned to validate the contract without necessarily requiring fulfillment.