Jesus was 30 years old when he began preaching, teaching and healing people. After he was baptized he went into the wilderness for 40 days and 40 nights.
Throughout this time He was tempted by the devil. Do you know how Jesus defeated the devil every time? Jesus used the word of God on the devil. What happened? The devil left and angels came and ministered to Jesus! The word of God is powerful! Satan flees from it, because he hates it.

The word of God is called a sword because it is very sharp. It penetrates the hearts of men and teaches them that they are sinful and in need of a Savior. 

 Don't ever be caught without your sword (Bible). This is a weapon that Satan will flee from.

 
This doesn't mean you have to carry your bible everywhere you go, but it does mean that we should have the word of God hidden in our hearts so that we will always be able to defend ourselves against Satan.

 

 

This is done by: reading, studying, memorizing scriptures, and living your life according to God's holy word.