The means needed to defy the devil’s roar is “in faith.” (The word “your” is not in the Greek; it is added in the translation for clarity.) The phrase “in faith” does not refer so much to knowledge of the content of faith (though that is needed) as working with the content of faith. So the term amounts to trust, working with the conviction that Christ Jesus has defeated Satan (Genesis 3:15; Colossians 2:15; 1 Peter 3:22).
9 Resist him, firm in your faith, knowing that the same kinds of suffering are being experienced by your brotherhood throughout the world.