St. Michael is an archangel who goes into battle before God for the people of God. His name means Who is like God?
Bearing the scales of justice and truth, St. Michael is believed to be the angel who accompanies us to heaven. He is the angel depicted in Revelations who leads the angels in the battle against Satan. Some believe Michael was the archangel who warned Mary and Joseph to flee to Egypt to save the life of the infant, Jesus.
Saint Michael is depicted brandishing a sword in triumph over Satan at his feet. He also holds the scales of justice (mercy) and truth above the head of Satan.
I have worn a St Michaels' medal for a few years. At first it was to remind me during a down time in our lives that not all things are just but we must hold on to truth. Later, I wore it to help keep me close to my son who not only joined the army but entered into Special Forces training. It gives me hope to know that our Special Forces understand the balance of truth and justice and that justice without mercy would only be revenge.
Who is like god? No one but God... The arrival of the baby King was an incarnation of love, mercy and truth on earth. Jesus came to teach us the delicate balance of truth and justice and that judgement was not a part of justice - just truth and mercy with love.
http://angels.about.com/od/SearchAngelsMiracles/p/Meet-Archangel-Michael.htm