Jesus Christ has a name that is above every other name. God is the greatest person in the universe, to be His son means you are great by birth.
Jesus has the blood of greatness flowing through his veins. By playing a role in creation, he became great by achievement. The Father also conferred a name on Him which is above all other names. Jesus is truly great. In the realm of the spirit, names are very important in securing spiritual deals. The name of Jesus has effect in all realms. He has power on Earth, in the lower heavens(hell or the underworld) and in the heaven of heavens.
Whenever we use or invoke His name, we release his power to work for us in all the realms. When on business for a great man, his power stands behind you to carry out business for him. In the same way, our faith in Jesus allows his power to back all we do in His name. By his name, we can dominate the earth, the lower heavens and the heaven of heavens. When we trust in Christ, the power in His name is available to us through the Holy Spirit.
Satan is constantly battling believers. Even though man is the head of creation, he sometimes need to fight to maintain dominion over the earth. The fall of man is the reason why man needs to fight to assert himself on earth. It is not possible for man to exercise authority over the devil in his own power. We need to use the name of Jesus to exercise and stand in the victory we received.