It was this song that the righteous King Alfred from England led his men 1200 years ago to sing when confronting the pagan hordes intent on invading England.    

When the enemy comes in a'roaring like a flood,
Coveting the kingdom and hungering for blood,
The Lord will raise a standard up and lead His people on,
The Lord of Hosts will go before defeating every foe; defeating every foe.
 
For the Lord is our defense, Jesus defend us,
For the Lord is our defense, Jesu defend.
 
Some men trust in chariots, some trust in the horse,
But we will depend upon the Name of Christ our Lord,
The Lord has made my hands to war and my fingers to fight.
The Lord lays low our enemies, but He raises us upright; He raises us upright. 
 
For the Lord is our defense, Jesus defend us,
For the Lord is our defense, Jesu defend.
 
A thousand fall on my left hand, ten thousand to the right,
But He will defend us from the arrow in the night.
Protect us from the terrors of the teeth of the devourer,
Embue us with your Spirit, Lord, encompass us with power; encompass us with power.
 
For the Lord is our defense, Jesus defend us,
For the Lord is our defense, Jesu defend.