Every Christian needs to know how to properly resist the Devil, so they can be most effective for God, and so they do not fall into sin and bring disgrace upon Christ.
The Bible says how we get rid of the Devil is too:
James 4:7 “Submit yourselves therefore to God. Resist the devil, and he will flee from you.”
Now, this does not mean that the Devil only fights people who are not submitted to God already.
Job was right with God and the Devil viciously attacked him. (See Job chapter 1)
Moreover, the Bible also says that we must put on the whole armour of God in order to properly resist the Devil.
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;”
Here are some practical things you can do to put on the armour of God, and make the Devil flee from you:
Pray a lot, keep God in all your thoughts (stay in an attitude of prayer constantly with thanksgiving).
1 Thessalonians 5:17 “Pray without ceasing.”
1 Thessalonians 5:18 “In every thing give thanks: for this is the will of God in Christ Jesus concerning you.”
Psalms 10:4 “The wicked, through the pride of his countenance, will not seek after God: God is not in all his thoughts.” (If God is not in all the thoughts of the wicked, then He should be in all the thoughts of a Christian.)
Philippians 4:6-9 “Be careful for nothing; but in every thing by prayer and supplication with thanksgiving let your requests be made known unto God. And the peace of God, which passeth all understanding, shall keep your hearts and minds through Christ Jesus. Finally, brethren, whatsoever things are true, whatsoever things are honest, whatsoever things are just, whatsoever things are pure, whatsoever things are lovely, whatsoever things are of good report; if there be any virtue, and if there be any praise, think on these things. Those things, which ye have both learned, and received, and heard, and seen in me, do: and the God of peace shall be with you.”
Read the Bible a lot (especially John and Psalms).
Psalms 119:50 “This is my comfort in my affliction: for thy word hath quickened me.”
Psalms 119:52 “I remembered thy judgments of old, O LORD; and have comforted myself.”
John 14:16 “And I will pray the Father, and he shall give you another Comforter, that he may abide with you for ever;”
John 14:18 “I will not leave you comfortless: I will come to you.”
John 14:26 “But the Comforter, which is the Holy Ghost, whom the Father will send in my name, he shall teach you all things, and bring all things to your remembrance, whatsoever I have said unto you.”
2 Peter 1:2 “Grace and peace be multiplied unto you through the knowledge of God, and of Jesus our Lord”
Listen to a lot of comforting and soothing Christian music, like Hymns, not Christian Rock.
Christian Rock will excite your emotions too much. You need to listen to calming Christian music, like hymns, so you can truly be still and know that God is God. (see Psalm 46:10)
You can find a lot of these kinds of videos on you tube, especially ones that are just instrumental.
Colossians 3:16 “Let the word of Christ dwell in you richly in all wisdom; teaching and admonishing one another in psalms and hymns and spiritual songs, singing with grace in your hearts to the Lord.”
Ephesians 5:17-20 “Wherefore be ye not unwise, but understanding what the will of the Lord is. And be not drunk with wine, wherein is excess; but be filled with the Spirit; Speaking to yourselves in psalms and hymns and spiritual songs, singing and making melody in your heart to the Lord. Giving thanks always for all things unto God and the Father in the name of our Lord Jesus Christ;”
Also, continually do things that you know pleases God, and don’t do anything that you know would displease Him.
Titus 3:8 “This is a faithful saying, and these things I will that thou affirm constantly, that they which have believed in God might be careful to maintain good works. These things are good and profitable unto men.”
2 Corinthians 13:11 “Finally, brethren, farewell. Be perfect, be of good comfort, be of one mind, live in peace; and the God of love and peace shall be with you.”
Now, the word perfect there does not mean that you can be completely sinless, but rather that you be submitted to Go by not intentionally sinning.
This is how you resist the Devil. If you keep doing these things the Devil will flee from you, and you will have peace.
However, as long as you are in this life, the Devil will probably come back and bother you again in time, but every time, just resist him like this, and he will leave.