What is the ruling on praying in large shoes, such as soldiers' boots?

A Muslim is permitted to pray while wearing shoes, as long as he is certain of their purity. The Prophet, peace and blessings be upon him, prayed in his sandals. If there is any impurity on them, it can be wiped off, and one may pray in them. However, in carpeted mosques, it is preferable to remove shoes so as not to soil the carpets.