The ruling on the prayer of one who wiped over a dirty sock while forgetting

Question:
May Allah reward you. This questioner says: A man wiped over his sock and prayed in it, then he remembered that the sock was dirty. Is his prayer valid?

Answer:
His prayer is valid. Even if he prayed in a dirty garment while forgetting the impurity, or did not know about it until after he had prayed, his prayer is valid.