Ephesians 6:17 King James Version (KJV)
And take the helmet of salvation, and the sword of the Spirit, which is the word of God:
Let me ask you a question. When Jesus encountered satan during the temptation of Christ, how did he fight the devil?
To everything satan brought up, Jesus replied, "It is written," and then He quoted scripture.
Jesus is our example; therefore, we need to fight in the same way - by quoting scripture.
The bible is not a magic charm whereby just carrying it gets rid of the enemy. The sword of the Spirit will do you no good if you have never studied or even read it. If you know and believe the Word, the Holy Spirit can bring to remembrance the scripture you need when situations arise. You can also be proactive. If you know the Word, you can pray scripture over someone's life, even before trouble happens!
The Word tells us to be watchful, awake and vigilant. Use your sword of the Spirit every day -don't start your day without it.
For further study:
1 Peter 5:8
This post is Day 24 of my series, 31 Basics for Believers. You can find all the posts here.