St. Michael the Archangel,
defend us in battle.
Be our defense against the wickedness and snares of the Devil.
May God rebuke him, we humbly pray,
and do thou,
O Prince of the heavenly hosts,
by the power of God,
thrust into hell Satan,
and all the evil spirits,
who prowl about the world
seeking the ruin of souls. Amen.
This is actually the short (and most familiar) version of the prayer. It was composed by Pope Leo XIII in 1886 after he saw a vision of demons trying their hardest to destroy the Church in the upcoming century. This prayer is part of the Leonine prayers which are typically prayed after the mass in the Extraordinary form. Obviously, this is a great prayer for everyone to pray daily!