Deuteronomy Chapter 20
Instructions Concerning Warfare
A. The spiritual and practical preparation of the army.
1. (Deuteronomy 20:1) The command to trust in God.
“When thou goest out to battle against thine enemies, and seest horses, and chariots, and a people more than thou, be not afraid of them: for the LORD thy God is with thee, which brought thee up out of the land of Egypt.”
Israel would often face enemies with greater numbers and superior military technology. Egypt, Assyria, and later Babylon fielded horses and iron chariots that Israel did not possess, making Israel appear weak by military standards. Yet God directly commands, “be not afraid of them.” Fear, in this context, is not simply emotional distress—it is unbelief that forgets the presence and power of God. The reason Israel was not to fear was not because the enemy was small, but because “the LORD thy God is with thee.” This is the same divine assurance given to Joshua when he faced Canaan’s fortified cities: “Have not I commanded thee? Be strong and of a good courage; be not afraid… for the LORD thy God is with thee whithersoever thou goest” (Joshua 1:9). God never denied the reality of the threat; He simply demanded that their faith be greater than the threat.
God anchors His command in His past faithfulness—“which brought thee up out of the land of Egypt.” Israel was to measure future battles by past deliverance. If God could break the power of Egypt, drown Pharaoh’s chariots in the Red Sea, and sustain Israel in the wilderness, then any enemy after that was lesser by comparison. God did not ask for blind faith, but faith rooted in His proven character. This same logic is used in Romans 8:31, “If God be for us, who can be against us?” One plus God is a majority, and no earthly force can overcome divine presence. Fear of man is ultimately a theology problem; it forgets who God is. Israel’s military strength did not rest in horses or chariots, but in obedience and trust in the Lord of Hosts. Psalm 20:7 says, “Some trust in chariots, and some in horses: but we will remember the name of the LORD our God.”
2. (Deuteronomy 20:2–4) The command to encourage the people before battle.
“And it shall be, when ye are come nigh unto the battle, that the priest shall approach and speak unto the people, And shall say unto them, Hear, O Israel, ye approach this day unto battle against your enemies: let not your hearts faint, fear not, and do not tremble, neither be ye terrified because of them; For the LORD your God is he that goeth with you, to fight for you against your enemies, to save you.”
Before swords were drawn or trumpets were sounded, the first voice the soldiers heard was not that of a general, but of a priest. This shows that war for Israel was never merely political or military—it was spiritual. The priest's duty was to remind the people of covenant promise, not military strategy. Israel’s confidence was not to come from formations, iron weapons, or numbers, but from the presence of God in their midst. The text uses four phrases for fear: “hearts faint,” “fear not,” “do not tremble,” and “neither be ye terrified”—showing how God addresses every degree of fear from inward anxiety to outward panic.
The reason they are not to fear is again theological—“For the LORD your God is he that goeth with you.” God does not send them into battle alone; He accompanies them. He is both Commander and Deliverer. The phrase “to fight for you” shows that God Himself takes the field against the enemy, as He did when He rained hailstones on the Amorites (Joshua 10:11), or when “the LORD set ambushments” against Moab and Ammon in the days of Jehoshaphat (2 Chronicles 20:22). Victory in war was never guaranteed based on national strength, but on spiritual condition. When Israel trusted and obeyed, they could not lose. But when Israel disobeyed—like at Ai in Joshua 7—even a small army could defeat them. Thus, success in battle depended not on swords but on sanctification. Holiness was Israel’s true warfare.
3. (Deuteronomy 20:5–9) How to shrink an army and make it more effective
“And the officers shall speak unto the people, saying, What man is there that hath built a new house, and hath not dedicated it? let him go and return to his house, lest he die in the battle, and another man dedicate it. And what man is he that hath planted a vineyard, and hath not yet eaten of it? let him also go and return unto his house, lest he die in the battle, and another man eat of it. And what man is there that hath betrothed a wife, and hath not taken her? let him go and return unto his house, lest he die in the battle, and another man take her. And the officers shall speak further unto the people, and they shall say, What man is there that is fearful and fainthearted? let him go and return unto his house, lest his brethren’s heart faint as well as his heart. And it shall be, when the officers have made an end of speaking unto the people, that they shall make captains of the armies to lead the people.”
God instructed Israel’s army to deliberately reduce its size before going to war. This is completely the opposite of human military strategy. Nations normally wanted as many soldiers as possible, but God wanted only those who were spiritually and mentally ready for battle. The officers were commanded to dismiss any man with unfinished obligations — a new house not dedicated, a vineyard not yet harvested, or a woman to whom he was betrothed but not yet married. These men were not condemned; rather, God was acknowledging the reality that divided loyalties make weak soldiers. A man whose heart is at home cannot fully commit to the battlefield. This principle is echoed spiritually in 2 Timothy 2:4, “No man that warreth entangleth himself with the affairs of this life.” God was teaching that His battles must be fought by those whose hearts are free from distraction.
Then God made an even more surprising exemption — any man who was “fearful and fainthearted” was to go home. Cowardice is contagious. One fearful man can weaken the heart of ten brave ones. Fear spreads faster than faith. This is why God warned, “lest his brethren’s heart faint as well as his heart.” The Lord wanted quality, not quantity. God would rather have a small army full of faith than a massive army full of fear. This same principle was demonstrated in the days of Gideon. Gideon began with 32,000 men. God said, “The people that are with thee are too many” (Judges 7:2). Twenty-two thousand fearful men left. Then nine thousand more were dismissed. In the end, only 300 remained, and God delivered Israel from a Midianite army of 135,000. This proves that God does not need numbers — He needs faith. “For the LORD saveth not with sword and spear: for the battle is the LORD’s” (1 Samuel 17:47).
These exemptions also revealed that Israel’s confidence was not in military might, but in the presence of God. No other nation sent soldiers home for these reasons. Pagan armies gloried in size and strength. Israel was to glory in God alone. It was a declaration to the world that victory belonged to the LORD, not to the power of man. Psalm 33:16–17 says, “There is no king saved by the multitude of an host: a mighty man is not delivered by much strength. An horse is a vain thing for safety.” This passage in Deuteronomy reflects that same truth. God can do more with a small devoted army than with a large distracted one.
Finally, captains were appointed to lead the remaining forces. God values order and leadership in His army. Even the most faithful soldiers require direction. This aligns with the principle seen throughout Scripture — God calls men to lead, whether in the home, church, or battlefield. 1 Corinthians 14:40 says, “Let all things be done decently and in order.” These captains were not chosen by popularity or rank, but by the call and command of God. A disciplined, obedient, faith-filled remnant will always outperform a massive army without conviction.
Deuteronomy 20:10–11
“When thou comest nigh unto a city to fight against it, then proclaim peace unto it. And it shall be, if it make thee answer of peace, and open unto thee, then it shall be, that all the people that are found therein shall be tributaries unto thee, and they shall serve thee.”
God prescribes rules for warfare, and here He sets forth the normal procedure for approaching a fortified place, showing that Israel’s wars were bound by divine law and moral restraint. The first act is an offer of peace, which demonstrates that God’s way is not bloodlust, but measured justice and an attempt at reconciliation where possible. The offer of peace recognizes human dignity and the possibility that a people will choose submission rather than destruction, a posture that preserves life and brings the city under Israel’s authority without needless slaughter, this is consistent with the deeper biblical ethic that seeks the restraint of conflict when possible, as Paul exhorts believers to pursue peace when it is within their power, “If it be possible, as much as lieth in you, live peaceably with all men” (Romans 12:18 KJV).
If the city accepts the terms and opens its gates, the result is subjection rather than extermination, the inhabitants become tributaries and servants, which secures Israel’s possession without annihilation, this outcome protected noncombatants and preserved resources for the nation, it also functioned as an instrument of covenant mercy when a people repented or chose submission rather than continued resistance. This procedure stands in contrast to the exceptional commands that sometimes accompanied specific divine judgments, for example the conquest of Canaan under the herem where God commanded destruction in certain cities because of their wickedness, an exception that does not negate the general rule here but rather underscores that some commands were unique and tied to God’s covenantal justice, see Joshua 6 for a case where special instruction governed the siege of Jericho.
These verses also anticipate later Christian reflection on the morality of war, where the ancient Christian tradition articulated criteria for just conduct in armed conflict, such as legitimate authority, just cause, right intention, and last resort, the Deuteronomic prescription for a prior offer of peace corresponds with the principle that war must be a last resort and that reconciliation should be sought first. The military procedures required by God combine prudence with righteousness, they enforce order and limit brutality, and they demonstrate that Israel’s warfare was not arbitrary but regulated by God’s revealed will, those who wage the Lord’s battles must therefore do so under His commandments, mindful that God’s aim is ultimately the restraining of evil and the restoration of peace when repentance is possible.
2. (Deuteronomy 20:12–15) Conquering a city through siege and battle
“And when thou shalt come nigh unto a city to fight against it, then proclaim peace unto it. And it shall be, if it make thee answer of peace, and open unto thee, then it shall be, that all the people that are found therein shall be tributaries unto thee, and they shall serve thee. And if it will not make thee answer of peace, but will make war against thee, then thou shalt besiege it. And when the LORD thy God hath delivered it into thine hands, thou shalt smite every male thereof with the edge of the sword.”
When a city refused peace and took up arms, Israel was to employ siege and martial force until the city was delivered into their hand. Siege warfare in the ancient Near East was the normal method for reducing fortified places, it involved cutting off food, water, and lines of communication until hunger, thirst, or internal collapse forced surrender, and the biblical text assumes realism about the brutality of ancient conflict while simultaneously providing a divinely ordered procedure meant to limit arbitrary slaughter and to regulate conduct. The command to “besiege it” presupposes patient, disciplined application of force rather than wanton massacre, because siege doctrine allowed opportunity for surrender, repentance, or submission, and it made the campaign a matter of covenant discipline under God rather than unchecked rage.
The instruction to “smite every male thereof with the edge of the sword” must be read in its historical and theological context, Israel’s covenant society understood adult males as the primary bearers of military threat, and ancient practice frequently treated surviving warrior-age males as continuing security risks who could rearm and revolt. The text therefore directs decisive neutralization of the male combat potential of a hostile city, while the following clause in the chapter makes clear that women, children, and livestock were taken as spoil, which functioned as the material recompense for the army and for the nation. This allocation of spoil was not mere greed, it was a pragmatic system for supplying the victors, settling displaced families, and undergirding the logistical expenses of war in an era without standing pay systems. Plunder as wages appears elsewhere in Scripture, for example in Samuel’s narratives where the spoils sustain the people after a campaign, showing continuity with the ancient economy of warfare.
Theologically, these harsh measures must be seen against several realities, first God’s sovereignty and judgment, He who gives the land and who determines its stewardship, uses even war as an instrument of justice and of advancing His purposes, second the necessity of national survival in a hostile environment, Israel’s existence depended on decisive actions when nations threatened covenant life, third the restraint implicit in the regulation, the text limits what is to be done by distinguishing between cities “very far from you” and the special treatment required for the cities of the nations nearest Israel, which the law treats differently as part of God’s particular judgment and holy war commands. Ancient examples of prolonged sieges in Scripture like the account of Samaria’s siege in 2 Kings 6:24–33 underscore how famine and desperation made siege a grim but effective method, and the story of Gideon in Judges 7 illustrates God’s power to deliver by means that expose human reliance on divine intervention rather than sheer numbers, reinforcing that Israel’s warfare remained under divine control and moral constraint.
Practically, commanders and officers in Israel were therefore required to apply both prudence and covenantal fidelity, they were to offer peace first when feasible, they were to besiege and reduce military resistance when necessary, and they were to recognize that the spoils and captives served the economic and juridical needs of the nation thereafter. The passage forces the reader to wrestle with the moral complexity of war as an instrument wielded by a holy God, a complexity later Christian thinkers summarized in principles of just conduct in war such as legitimate authority, just cause, and proportionality, even though the Old Testament law applies those principles within a covenantal framework that differs from later Christian formulations.
3. (Deuteronomy 20:16–18) The command to utterly destroy the Canaanites
“But of the cities of these people, which the LORD thy God doth give thee for an inheritance, thou shalt save alive nothing that breatheth: But thou shalt utterly destroy them, namely, the Hittites, and the Amorites, the Canaanites, and the Perizzites, the Hivites, and the Jebusites, as the LORD thy God hath commanded thee: That they teach you not to do after all their abominations, which they have done unto their gods, so should ye sin against the LORD your God.”
Unlike the distant cities that could be offered peace, the Canaanite nations were to receive no terms of surrender. This was not merely warfare, this was divine judgment executed through Israel. God commanded that nothing that breathes be left alive, meaning men, women, and even children. This command was unique, limited to the inhabitants of Canaan, because this land was Israel’s inheritance under the Abrahamic covenant, and the wickedness of these nations had reached its fullest measure. God told Abraham generations earlier, “the iniquity of the Amorites is not yet full” (Genesis 15:16), but by the time of Joshua and Deuteronomy, it was full. Their religion involved child sacrifice to Molech, ritual prostitution, bestiality, necromancy, and occult practices, as seen in Leviticus 18:24–30, where God warns Israel not to imitate those very sins lest the land vomit them out as it did those before them. Their destruction was not ethnic cleansing, but moral cleansing, the holy wrath of God upon persistent, unrepentant evil. Just as God later judged Israel using Babylon when Israel fell into idolatry, so now He was using Israel as His instrument of judgment against the Canaanites.
The purpose of total destruction is clearly given, “that they teach you not to do after all their abominations.” God knew that if the Canaanites were allowed to remain, they would corrupt Israel morally and spiritually. This warning came to pass when Israel failed to fully obey. In Judges 1–2, Israel allowed Canaanites to remain, and their children intermarried with them and worshiped Baal. Solomon later sinned by marrying pagan women, who “turned away his heart after other gods” (1 Kings 11:4). This command, therefore, protected Israel from corruption and preserved true worship. The severity of the command reflected the severity of sin in God’s eyes. God is love, but God is also holy and just. His patience has limits when nations fill themselves with bloodshed and perversion. The flood of Noah and the destruction of Sodom show the same principle, God judges societies that become ripe with depravity.
4. (Deuteronomy 20:19–20) The command to save fruit trees during a siege
“When thou shalt besiege a city a long time, in making war against it to take it, thou shalt not destroy the trees thereof by forcing an axe against them, for thou mayest eat of them, and thou shalt not cut them down, (for the tree of the field is man's life,) to employ them in the siege: Only the trees which thou knowest that they be not trees for meat, thou shalt destroy and cut them down, and thou shalt build bulwarks against the city that maketh war with thee, until it be subdued.”
Even in war, God enforced restraint and wisdom. When Israel laid siege to a city, they were forbidden from cutting down fruit-bearing trees. These trees produced food, and God calls them “man’s life,” recognizing that ongoing survival for future generations depended on them. Pagans practiced scorched-earth tactics, destroying land to weaken enemies, but God forbade Israel from such wastefulness. War did not suspend morality. God expected His people to think generationally, to preserve the land He was giving them. They could only use non-fruit-bearing trees for siegeworks, ladders, ramps, battering structures, and fires. This command revealed that God’s law shaped not only worship and morality, but agriculture, ecology, and national policy. God cares about future provision, not just present victory.
This principle reflects wisdom found elsewhere in Scripture. Proverbs 12:10 says, “A righteous man regardeth the life of his beast,” meaning the godly care about sustaining life rather than destroying it needlessly. The land belonged to God, and Israel was merely a steward. By protecting fruit trees, God ensured that even war did not justify reckless destruction. Spiritually, this teaches that God’s people must never sacrifice long-term faithfulness for short-term gain. It also anticipates the millennial kingdom, where swords are beaten into plowshares and creation flourishes under the rule of the Messiah (Isaiah 2:4).
