Ephesians 6:10-18 "Finally, my brethren, be strong in the Lord, and in the power of his might. Put on the whole armour of God, that ye may be able to stand against the wiles of the devil. For we wrestle not against flesh and blood, but against principalities, against powers, against the rulers of the darkness of this world, against spiritual wickedness in high places. Wherefore take unto you the whole armour of God, that ye may be able to withstand in the evil day, and having done all, to stand. Stand therefore, having your loins girt about with truth, and having on the breastplate of righteousness; And your feet shod with the preparation of the gospel of peace; Above all, taking the shield of faith, wherewith ye shall be able to quench all the fiery darts of the wicked. And take the helmet of salvation, and the sword of the Spirit, which is the word of God:
Praying always with all prayer and supplication in the Spirit, and watching thereunto with all perseverance and supplication for all saints;"

2 Corinthians 2:11  "Lest Satan should get an advantage of us: for we are not ignorant of his devices."

Daniel 10:13-14  "But the prince of the kingdom of Persia withstood me one and twenty days: but, lo, Michael, one of the chief princes, came to help me; and I remained there with the kings of Persia. Now I am come to make thee understand what shall befall thy people in the latter days: for yet the vision is for many days."