Angel means "messenger." God frequently used angels to announce important events in the history of salvation including the birth of Jesus, the birth of John the Baptist, and the resurrection of Jesus from the dead.
The angels are spirit beings who were created holy. The Bible tells us that they are powerful and many and that they serve God and help us. Hebrews 1:14 teaches, "Are not all angels ministering spirits sent to serve those who will inherit salvation?" Take a look at 2 Kings 6:15-17 to see how the heavenly hosts protected Elisha and his servant.
Some angels rebelled against God. They are the devils or demons. Evil angels are also many and powerful. They hate God and seek to destroy everything that is good, especially faith in Christ. In the first epistle of Peter, he wrote, "Be self-controlled and alert. Your enemy the devil prowls around like a roaring lion looking for someone to devour."
It is important to understand that evil angels made themselves evil. Their disobedience got them thrown out of heaven. For them there is no hope of redemption. We cannot overcome such demons by our own strength. They are overcome by the aid of Christ Jesus who is stronger than the strongest demon. Christ crushed the head of the slithering Satan when the Lord rose victoriously from the dead. Christ's disciples, who arm themselves with the word of God can withstand the deadly temptations of Satan. The devil cannot stand up against the Holy Scriptures. Frustrate the devil's evil plans - put on the Word of God today!