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 night. Throughout this times He was tempted by the devil. Do you know how Jesus defeated the devil every time He tried to attack Him. 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 fees 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 that they need a Savior.