Deuteronômio 20:4+ - Bíblia Online

When thou goest out to battle against thine enemies and seest horses and chariots [and] a people more than thou, do not be afraid of them; for the LORD thy God [is] with thee, who brought thee up out of the land of Egypt. 
And it shall be, when ye are come near 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 goes with you to fight for you against your enemies, to save you. 
And the officers shall speak unto 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 peradventure he die in the battle and another man dedicate it. 
And who has planted a vineyard and has not [yet] eaten of it? Let him [also] go and return unto his house lest peradventure 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 unto his house lest peradventure 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 a coward at heart? Let him go and return unto his house that he not cause his brethren's hearts to become as his heart. 
And it shall be when the officers have finished speaking unto the people that the captains of the armies shall lead before the people. 
When thou comest near to a city to fight against it, then proclaim peace unto it. 
And it shall be, if it makes thee an answer of peace and opens unto thee, [that] all the people [that are] found therein shall be tributaries unto thee, and they shall serve thee. 
And if it will make no peace with thee but will make war against thee, and if thou should besiege it, 
and if the LORD thy God should deliver it into thine hands, then thou shalt smite every male thereof with the edge of the sword. 
Only the women and the little ones and the animals and all that is in the city, all the spoil thereof, shalt thou take unto thyself; and thou shalt eat of the spoil of thine enemies, which the LORD thy God has given thee. 
Thus shalt thou do unto all the cities [which are] very far off from thee, which [are] not of the cities of these Gentiles. 
Only of the cities of these peoples, which the LORD thy God gives thee [for] an inheritance, thou shalt save alive nothing that breathes; 
but thou shalt utterly destroy them: the Hittite and the Amorite, the Canaanite and the Perizzite, the Hivite and the Jebusite, as the LORD thy God has commanded thee, 
that they not teach you to do after all their abominations, which they do unto their gods, lest ye should sin against the LORD your God. 
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 may 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 [are] not trees for food, thou shalt destroy and cut them down; and thou shalt build bulwarks against the city that makes war with thee, until it is subdued.: 
Deuteronômio 21