In Exodus 3:1-5, God told Moses to remove his shoes because the ground that he was standing on was Holy Ground. Moses was about to receive a very important assignment and this ‘holy ground moment’ was preparing Moses to accept it. In Joshua 5:13-15, God told Joshua the same thing; he was also about to receive an important assignment - to lead the Children of Israel into the Promised Land.  The presence of a Holy God changes everything; it even makes the very ground we stand upon, holy.  Both Moses and Joshua worshipped when they became aware of His presence.  It is the only thing we can do when the presence of our  Supernatural God comes into our natural space.