Though the ultimate war has been won, we are engaged in a daily battle against the prince of this world.
We are clearly warned in God's Word of the damage that can be inflicted by the kingdom of darkness.
The Enemy schemes against us, throws flaming missiles at us, seeks to devour us, and wages direct warfare upon us Ephesians 6:11-12,16; 1 Peter 5:8; John 10:10)
As a result, we are to arm ourselves, stand against, refute, resist and overcome (Ephesians 6:12-18; James 4:7; Revelation 12:11).
Everything we need to successfully do battle was appropriated on the Cross. We simply need to appropriate it.
Ephesians 6: 11-20 "Put on the whole armor of God, that you may be able to stand against the schemes of the devil. 12 For we do not wrestle against flesh and blood, but against the rulers, against the authorities, against the cosmic powers over this present darkness, against the spiritual forces of evil in the heavenly places. 13 Therefore take up the whole armor of God, that you may be able to withstand in the evil day, and having done all, to stand firm. 14 Stand therefore, having fastened on the belt of truth, and having put on the breastplate of righteousness, 15 and, as shoes for your feet, having put on the readiness given by the gospel of peace. 16 In all circumstances take up the shield of faith, with which you can extinguish all the flaming darts of the evil one; 17 and take the helmet of salvation, and the sword of the Spirit, which is the word of God, 18 praying at all times in the Spirit, with all prayer and supplication. To that end, keep alert with all perseverance, making supplication for all the saints, 19 and also for me, that words may be given to me in opening my mouth boldly to proclaim the mystery of the gospel, 20 for which I am an ambassador in chains, that I may declare it boldly, as I ought to speak.
1 Peter 5:8 Be sober-minded; be watchful. Your adversary the devil prowls around like a roaring lion, seeking someone to devour.
John 10:10 The thief comes only to steal and kill and destroy. I came that they may have life and have it abundantly.
James 4:7 Submit yourselves therefore to God. Resist the devil, and he will flee from you.
Revelation 12:11 And they have conquered him by the blood of the Lamb and by the word of their testimony, for they loved not their lives even unto death.