Satan uses many weapons against Christians, but there is one thing he likes to use most, his “kryptonite” for believers, that weakens them like no other weapon could.

Jon Bloom, contributing author at Desiring God, said faith-filled, Spirit-filled believers are so powerful—and a unified community of such believers even more powerful—that Satan fears what they can do.

“Nothing on earth is more powerful than the Holy Spirit flowing through the faith of a born again disciple of Jesus,” Bloom wrote in an article. “When a Christian is full of Spirit-empowered faith, he cannot stop and cannot be stopped speaking about what he has seen and heard (Acts 4:20). Not even death can silence him (Hebrews 11:4).”

However, Bloom said, believers have one weakness: unbelief.

“It weakens us and can destroy us,” he said.

And because Satan knows this very well, his “primary goal” is to attack an individual Christian’s faith. When dealing with a community of believers, Satan creeps in to divide the church in order to break “united faith” and leave some members of the church isolated.

This strategy makes both the believer and the church weak and vulnerable to more attacks. Bloom said Satan’s forces are “hell-bent on these strategic objectives (Ephesians 6:11-12).”

But why does Satan specifically target a Christian’s faith?

“The faith of a Christian is God’s chosen channel to bring his saving, sanctifying, strengthening, healing, and delivering grace to the world,” Bloom said.

Satan can effectively immobilize a Christian by weakening his or her faith. And when he has done so, the Christian can be tempted to disobey, be anxious, be fearful, be distracted and doubt God and fellow believers.

Preacher and author John Piper said all sins stem from having unbelief in our hearts.

“Anxiety, misplaced shame, indifference, regret, covetousness, envy, lust, bitterness, impatience, despondency, pride — these are all sprouts from the root of unbelief in the promises of God,” he wrote in an article.

However, God has not left His children without weapons to fight back, and there is a way to beat the father of lies and master accuser. Here are some things you can do.

Repent of your unbelief and remember the source of your faith. Bloom cited the story of Peter who walked on water but began to sink when his focus shifted from Jesus to the waves. As a believer, you must keep your eyes on Jesus to ward off unbelief.

Fill you heart with God’s promises from the Bible that specifically target your unbelief. Bloom called this “soaking” and "bathing" in God’s promises until you overcome your unbelief. Get to the Word, read it, meditate on it and live it.

Find people to stand with you in prayer. Piper said Christians must surround themselves with other believers who will pray with them and encourage them. Even the great apostle Paul never traveled alone. He had Barnabas, Timothy, Luke, Silas and others.

All Christians battle unbelief the moment they receive Christ as their Savior. However, it is not a battle that Christians can't win.

“The new birth introduces a person into a life of warfare,” Piper said. “In other words, the most basic battle of our life is the battle to believe in the living God, and not to allow our heart to become an evil heart of unbelief.”

“So I urge you in your warfare, take up the book of God, ask the Holy Spirit for help, lay the promises up in your heart, and battle on,” he said.