In times of war food, water and sanitation all become compromised. All of these three God had specific rules, laws and regulations about because he cares for us and wants us to have a good life.
This portion of scripture is all about covenant. If you do this then I will do that. This is the wording of a covenant. Deut. 30:15 "I have set before you today life and prosperity or death and adversity" Even covenant Israel had to choose! This is referring to the blessing and cursing (cf. Deuteronomy 27-28). Remember the choice is set in a covenant of grace. This is very similar to Wisdom Literature's idiom of the "two ways" (cf. Pro. 4:10-19; Jer. 21:8; Matt. 7:13-14). Our choices show who we are! How we respond to life's inexplicable "in and outs" reveals our spiritual orientation!