What is the ruling on someone who entered the Grand Mosque wearing clothes and shoes that he knew to be ritually impure, and is expiation required of him, and what are the implications for him and his wife?

If someone has impurity (najāsa) on their clothes, body, or shoes, it is forbidden for them to enter the mosque with it if they fear it will contaminate the mosque. It is disliked (makrūh) if they are certain it will not cause contamination, based on the hadith of Anas (may Allah be pleased with him): "Indeed, these mosques are not suitable for any of this urine or filth; rather, they are only for the remembrance of Allah and the recitation of the Qur'an."

As for performing prayer (salat) or circumambulation (tawaf) with such impurity, it is not valid, due to the condition of purification from ritual impurity (hadath) and physical impurity (najāsa). Whoever circumambulates or prays while knowingly having impurity is sinful. However, if one becomes aware of the impurity after the prayer or circumambulation, there is no sin upon them, and their prayer is valid according to the preponderant opinion.