Satan uses our 'fleshly weakness' to lead us into temptation. The first temptation Jesus faced in the wilderness was 'the lust of the flesh'. Just as it was then, in today's world this is the desire of material things such as food, clothing, money, etc. instead of trusting God for our provision of these things, specifically the 'spiritual food's that only God can give!
I do not think the settlers were justified in expanding west, because the territory was already claimed by the Native Americans. I do understand the promise the promise that was made, but the settlers had no right to try to settle in the west.
