Power of a man is his abilities and man's limitation is thinking he is not perfect. We think about our limitations more than on strengths. We don't focus and try to take advantage of our abilities but focus on our weaknesses and loose.
Man' power is that he can steer the life of other creatures while his limitation is God can steer our lives. Thus, there is a hierarchy in the system man can control some creatures such as animals and other living beings and so can the God by controlling us. We all are a part of a bigger system than we can understand. These are the powers and limits of man according to pope.