Deuteronomy20

When you go out to battle against your enemies, and see horses, and chariots, and a people more than you, be not afraid of them: for the LORD your God is with you, which brought you up out of the land of Egypt.

And it shall be, when you are come near to the battle, that the priest shall approach and speak to the people,

And shall say to them, Hear, O Israel, you approach this day to battle against your enemies: let not your hearts faint, fear not, and do not tremble, neither be you terrified because of them;

For the LORD your God is he that goes with you, to fight for you against your enemies, to save you.

And the officers shall speak to the people, saying, What man is there that has built a new house, and has 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 has planted a vineyard, and has not yet eaten of it? let him also go and return to his house, lest he die in the battle, and another man eat of it.

And what man is there that has betrothed a wife, and has not taken her? let him go and return to his house, lest he die in the battle, and another man take her.

And the officers shall speak further to the people, and they shall say, What man is there that is fearful and fainthearted? let him go and return to 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 to the people that they shall make captains of the armies to lead the people.

When you come near to a city to fight against it, then proclaim peace to it.

And it shall be, if it make you answer of peace, and open to you, then it shall be, that all the people that is found therein shall be tributaries to you, and they shall serve you.

And if it will make no peace with you, but will make war against you, then you shall besiege it:

And when the LORD your God has delivered it into your hands, you shall smite every male thereof with the edge of the sword:

But the women, and the little ones, and the cattle, and all that is in the city, even all the spoil thereof, shall you take to yourself; and you shall eat the spoil of your enemies, which the LORD your God has given you.

Thus shall you do to all the cities which are very far off from you, which are not of the cities of these nations.

But of the cities of these people, which the LORD your God does give you for an inheritance, you shall save alive nothing that breathes:

But you shall utterly destroy them; namely, the Hittites, and the Amorites, the Canaanites, and the Perizzites, the Hivites, and the Jebusites; as the LORD your God has commanded you:

That they teach you not to do after all their abominations, which they have done to their gods; so should you sin against the LORD your God.

When you shall besiege a city a long time, in making war against it to take it, you shall not destroy the trees thereof by forcing an ax against them: for you may eat of them, and you shall not cut them down (for the tree of the field is man's life) to employ them in the siege:

Only the trees which you know that they be not trees for meat, you shall destroy and cut them down; and you shall build bulwarks against the city that makes war with you, until it be subdued.