A type of warfare described in the book of Deuteronomy, especially in chapter 20. Holy war was not just fought by kings and their trained soldiers. It is seen as God’s war. God is directly involved alongside his covenant people, who are chosen to fight in his name.
The size of the army was not important. Sometimes the numbers were even reduced to show that victory came not from military strength, but from God's action against his enemies. When Israel obeyed God and followed his battle instructions, the war was within God's will. God commanded it, and his people trusted him in battle.
God is called “a man of war,” and the Bible says that “the battle is the LORD’s” (1 Samuel 17:47; compare 18:17; 25:28). With this faith, it is easy to see how the Israelites understood holy war as a way God worked through them. They believed their enemies were also God's enemies. They thought God would use them to fulfill his saving purposes for the world.
Examples of Holy War in the Bible
Moses believed that God declared war and sent his people to fight (Exodus 17:16; Numbers 31:3). At key moments in war, "the terror of the Lord" fell on the enemy. This allowed Israel's smaller army to defeat armies that were much larger (Joshua 10:10–14; Judges 4:12–16; 2 Samuel 5:24–25).
In a time of military crisis, the prophet Elisha was able to see God’s heavenly army surrounding Samaria, ready to defeat the powerful Syrian armies. Elisha prayed, and the Syrian soldiers were blinded and became powerless against Israel (2 Kings 6:15–23).
How Israel Sought God's Guidance in War
Different methods were used to discover God’s will and to ensure his active participation in battle. These included:
messages from prophets (1 Kings 22:5–23),
special objects used to determine God's will called Urim and Thummim (Exodus 28:30; Leviticus 8:8),
a priestly garment called the ephod (1 Samuel 30:7), and
the ark of the covenant.
Israel's leaders sought God's guidance for their military strategies. No steps were taken without God's approval and guidance (2 Samuel 5:19–23).
Holy War and the Promised Land
Since God promised the land of Canaan to the people of Israel, it was indeed the promised land. The Bible describes it as belonging to them by divine covenant (a binding agreement made by God with his people). The promised land was in that sense "the Holy Land." Defending this land against invaders was considered a holy war. The invading enemy was trespassing on holy territory that belonged to God's people by unchangeable decree. So invading the promised land brought God's judgment upon themselves.
The Complete Destruction of Enemies
From this perspective, the complete destruction of Israel's enemies was necessary. This was especially true for pagan, corrupt enemies. The Hebrew word herem originally meant "devoted." It came to mean "devoted to destruction" as something hostile to the rule of God (Joshua 6:17–18). God's plan must not be hindered, blocked, or stopped by any degrading idolatry or corrupting immorality (Deuteronomy 7).
Enemy cities within the promised land were to be completely destroyed (a practice known as "the ban"). Only silver, gold, and bronze and iron vessels were to be spared. They were placed in God's treasury as holy items (Joshua 6:17–21; 1 Samuel 15:3).
Holy War and God's Future Peace
There was a distinct forward-looking aspect to the concept of holy war. It looked beyond God's victories in specific battles to the end of all war and conflict. It pointed to a final time of peace that will prove the righteousness and sovereignty of God's saving purposes. It will also show God's concern and goal for his own people.
A final time of peace will come after God defeats all evil. After this, weapons of war will be turned into tools for peace (Isaiah 2:4; Micah 4:3). This will happen under the rule of the Messiah (God’s chosen leader), the Prince of Peace (Isaiah 9:6). He will triumph over all of God’s enemies on the great Day of the Lord (Psalm 110; Daniel 7; Zechariah 14).