What is the ruling on the prayer of a man whose khuffs became impure after he put them on while in a state of purity, then he wiped over them, took them off, and prayed without them?

Whoever wears his khuff (leather socks) after performing ablution (tahara) is permitted to wipe over them. If a impurity (najasa) touches the cuff in the area of wiping, he should remove it and then wipe. If the impurity is on the inner part, his wiping is valid before removing it, but it is obligatory to wash it for prayer.

As for removing the khuff after wiping, there is a difference of opinion: The majority: Ablution is invalidated by removing them, and one must repeat ablution or wash the feet only. Consequently, this man's prayer is invalid, and he must repeat it. Shaykh al-Islam Ibn Taymiyyah and those who agreed with him: Ablution is not invalidated by removing them. Consequently, this man's prayer is valid.

It is safer (more cautious) to repeat it, even though the opinion of non-invalidation is strong.