Ask for St. Gabriel's intercession, that he may drive away the spirits of evil that attack the Church.
St. Gabriel the Archangel is most well-known as the angel present at the Annunciation to Mary, inviting Mary to say “Yes” to God’s divine plan.
At the same time, he is often invoked for his angelic protection, asking him to defend the Church from the evil spirits roaming around the world.
Here is a prayer from Dom Prosper Gueranger’s Liturgical Year that asks for his special protection against evil.
Pray, O Gabriel, for the Church militant,
and defend her against the attacks of hell.
The times are evil the spirits of malice are let loose,
nor can we make stand against them unless with God’s help.
It is by His holy angels that He gives victory, to His bride.
Be thou, O strength of God, foremost in the ranks.
Drive heresy back, keep schism down, foil the false wisdom of men,
frustrate the policy of the world, arouse the well minded from apathy,
that thus the Christ whom thou didst announce may reign over the earth He has redeemed,
and that we may sing together with thee and the whole angelic choir,
“Glory be to God, peace to men!”