"In addition to all, [take] up the shield of faith with which you will be able to extinguish all the flaming missiles of the evil one" (Eph. 6:16).Satan's flaming arrows come in many forms: solicitations to impurity, selfishness, doubt, fear, disappointment, greed, vanity, covetousness, and the like. But whatever the specific form, all are seducing temptations aimed at eliciting ungodly responses.
Your faith protects you from such attacks when you elevate God's will above Satan's in your life. When tempted by Satan, Jesus responded by saying in effect, "I will not violate my Father's will by yielding to your devious schemes. In His own time He will feed Me, anoint Me as Messiah, and give Me the kingdoms of the world. I will not elevate your will and timing above His" (Matt. 4:1-11).
Jesus could have created food. He is the Messiah and the sovereign Lord over the kingdoms of the world. But He trusted the Father and yielded to His will, even though it meant personal discomfort and, eventually, the cross. When Satan saw that Jesus' trust in the Father was unshakable, he left Him (v. 11). That's the power of faith.
~John MacArthur, Drawing Near for September 19, 2013
As a believer, the shield that protects you is your faith in God. If you never question His character, power, or Word, you'll never fall victim to Satan's attacks. That doesn't mean he won't beseige you--but when he does, his assaults will be ineffective.
~John MacArthur, Drawing Near for September 18, 2013