You can pray this prayer when you need protection. This prayer is inspired by Psalm 27. The world tries to convince us that the peace and prosperity of man will save us. But our soul yearns for an eternal answer. The only real security we have is in Christ Jesus.
Traditional Prayer to St. Michael the Archangel for protection against Satan and all evil spirits "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 Divine power of God, cast into hell Satan and all the evil spirits who wander throughout the world seeking the ruin of souls. Amen."