In the eyes of the slave the world based on the exercise of power. The idea of the slave ethic appears throughout the Bible. The second aspect of the slave ethic, the feeling of constant deprivation, is expressed in the many warnings to the Israelites not to abuse their power in their relations towards the weak. Beyond the literal meaning of this verse is just the reason that G-d fears the Israelites might oppress the stranger. Since we ourselves were slaves, we might abuse our power and feel vulnerable yet upright in this situation.
War demands the use of power in order to defeat the enemy.
This situation is even true in circumstances where war is justified and its aims are honorable. Having power can lead to ethical decay for anyone particularly when an individual has been raised in conditions where power forms the basis for relations between individuals in the society. To combat these influences Moses gives laws to the Israelites to limit their use of power and their abuse of power towards the weak. In three cases of confrontation in this week's Torah portion, crossing through the border of Moab, Seir, and Ammon, the Israelites are commanded not to provoke these peoples and not to make war with them. In the fourth struggle, the conflict with Sihon, although G-d commands Moses to wage war and is explicit about the certainty of war, Moses still sends angels to Sihon with words of peace.