What is the significance of adding "fiery" to Ephesians 6:16? Ephesians 6:13–17 (NLT)
  
  &nbsp;13 Therefore, put on every piece of God’s armor so you will be able to resist the enemy in the time of evil. Then after the battle you will still be standing firm. 14 Stand your ground, putting on the belt of truth and the body armor of God’s righteousness. 15 For shoes, put on the peace that comes from the Good News so that you will be fully prepared. 16 In addition to all of these, hold up the shield of faith to stop the fiery arrows of the devil. 17 Put on salvation as your helmet, and take the sword of the Spirit, which is the word of God.  


[Emphasis mine.]

Is the fact that these arrows are on fire of any significance?
As I learned from my pastor a while ago, archers of the time would light their arrows on fire in an attempt to set wooden shields on fire and thus rob soldiers of any significant protection. In response to this, the Romans developed shields that had a gap in between the outer and inner plates. As such, flaming arrows would actually be extinguished by the lack of oxygen in between the wooden plates. Similarly, our faith should be like that; extinguishing the flaming arrows of the evil one and preventing continual damage.