It's a prayer to Saint Micheal, the Archangel.
The prayer itself is a bit different from the one in the game, maybe they cut out some words just for rating... But the original prayer is like this:
"Saint Michael the Archangel,
defend us in battle;
be our protection against the wickedness and snares of the devil.
May God rebuke him, we humbly pray:
and do thou, O Prince of the heavenly host,
by the power of God,
thrust into hell Satan and all the evil spirits
who prowl about the world seeking the ruin of souls.
The last five verses are the ones at the game.
Hope it helped!