Deuteronomy 19:14-20:9

You shall not move your countryman's landmarks, set up by previous generations, in the property that will be allotted to you in the land that the Lord your God is giving you to possess. A single witness may not validate against a person any guilt or blame for any offense that may be committed; a case can be valid only on the testimony of two witnesses or more. If a man appears against another to testify maliciously and gives false testimony against him, the two parties to the dispute shall appear before the Lord, before the priests or magistrates in authority at the time, and the magistrates shall make a thorough investigation. If the man who testified is a false witness, if he has testified falsely against his fellow, you shall do to him as he schemed to do to his fellow. Thus you will sweep out evil from your midst; others will hear and be afraid, and such evil things will not again be done in your midst. Nor must you show pity: life for life, eye for eye, tooth for tooth, hand for hand, foot for foot. When you take the field against your enemies, and see horses and chariots--forces larger than yours--have no fear of them, for the Lord your God, who brought you from the land of Egypt, is with you. Before you join battle, the priest shall come forward and address the troops. He shall say to them, "Hear, O Israel! You are about to join battle with your enemy. Let not your courage falter. Do not be in fear, or in panic, or in dread of them. For it is the Lord your God who marches with you to do battle for you against your enemy, to bring you victory." Then the officials shall address the troops, as follows: "Is there anyone who has built a new house but has not dedicated it? Let him go back to his home, lest he die in battle and another dedicate it. Is there anyone who has planted a vineyard but has never harvested it? Let him go back to his home, lest he die in battle and another harvest it. Is there anyone who has paid the bride-price for a wife, but who has not yet married her? Let him go back to his home, lest he die in battle and another marry her." The officials shall go on addressing the troops and say, "Is there anyone afraid and disheartened? Let him go back to his home, lest the courage of his comrades flag like his." When the officials have finished addressing the troops, army commanders shall assume command of the troops.