1 Corinthians 16:13-14

(13) Be on your guard; stand firm in the faith; be men of courage; be strong. (14) Do everything in love. 

There are many examples of courage through faith in the Bible, such as Daniel in the lion's den or David facing off against Goliath but I think Paul is going deeper than just standing uo against our adversaries. Of course he does mean to use your faith as a shield if you find yourself being persecuted as a believer in Christ but I do believe he also means that we need to have courage when we face ourselves.

Our own human nature is the most dangerous and deadly obstacle to our faith. Nothing puts our conviction to the test more than our own carnal minds. We have to constantly be on our guard, as Paul states, to subdue the evil thoughts and actions provoked by our own nature. We must be strong and have the courage to do what's right. How we think and act torwards others is the end result. If we walk in faith and love and combat our very own nature with weapons of love that GOD has provided for us, then we can slowly tame our evil nature and grow our spiritual side into something worthy of GOD's grace.