The Christian, having "done all to stand", (Ephesians 6:13), should therefore stand up in this world. "Let your light so shine before men, that they may see your good works, and glorify your Father which is in heaven.", (Matthew 5:16). "What shall we then say to these things? If God be for us, who can be against us, (Romans 8:31)? The faithful Christian has nothing to fear with God on their side.
"having your loins girt about with truth"
Truth is the foundation for all Christian exercises.
"and having on the breastplate of righteousness"
The breastplate is the armor that covered the body from the neck to the thighs, and consisted of two parts, one covering the front and the other the back. It was made of rings, or in the form of scales, or of plates, so fastened together that they, would be flexible, and yet guard the body from a sword, spear, or arrow. It is referred to in the Scriptures as a "coat of mail", (1 Samuel 17:5), and a "habergeon", (Exodus 28:32).
As the breastplate defended the soldier, righteous integrity defends the Christian.
Righteousness is rightful living. The obedient Christian who loves his neighbors, keeps himself unspotted from the world, diligently seeks God's will and walks upright shields them self from the fiery darts of the wicked. The Devil is battling for the hearts of mankind. He does this by stamping out righteous living.