Taken from Little Pictorial Lives of the Saints:
“MI-CA-EL,” or “Who is like unto God?” was the cry of the great Archangel when he smote the rebel Lucifer in the conflict of the heavenly hosts. From that hour he has been known as Michael, Captain of the armies of God, the archetype of divine fortitude, the champion of every faithful soul in strife with the powers of evil. What is more, we see him in Holy Scripture as the special guardian of the children of Israel, their comfort and protector in times of sorrow or conflict. It is he who prepares their return from the Persian captivity, when the prophet Daniel prays for that favor (Daniel 10:12-13); who leads the valiant Maccabees to victory in battle, after the prayer of Judas Maccabeus (I Mac. 7:41-44).
Ever since its foundation by Jesus Christ, the Church has venerated Saint Michael as her special patron and protector. She invokes him by name in her Confiteor, when accusing her faults; she summons him to the side of her children in the agony of death, and chooses him as their escort from the chastening flames of purgatory to the realms of holy light. Lastly, when Antichrist shall have set up his kingdom on earth, it is Michael who will unfurl once more the standard of the Cross. This we know from a prophecy of Scripture which states clearly that in those days the great prince Michael will rise up to protect the children of God. (Daniel 12:1-4)
During the plague in Rome in the 6th century, Pope Gregory the Great saw Saint Michael in a vision sheathing his flaming sword to show that he would put an end to the scourge which was ravaging the city. In 608 a church was erected in thanksgiving to Saint Michael for the help he gave.
Reflection: Saint Bernard wrote: “Whenever any grievous temptation or vehement sorrow oppresses you, invoke your Guardian, your Leader. Cry out to him and say, Lord, save us, lest we perish!”