There are many places in the written revelation of God where we see God laying down different options before us. Because God is not the author of confusion, His line is always distinct. And, His promises and threats are never hollow. He always comes through. Now, in this chapter God juxtaposes the potential blessings of spiritual consummation against the consumption that was sure follow national disobedience.
This section is commenced with an optimistic perspective. It was an if/then proposition. If the people would obey, then God promised to: give rain as it was needed, bless the agricultural efforts of the people, provide them with enough food, keep them safe, give them peace, give them confidence, remove dangerous wild animals from their coasts, prevent famines, give them victory in their battles, pay attention to them, increase their population, give them more than they could handle, dwell among them and be their God. It sounds like a very good deal that God was offering to them, no?
On the other hand, the passage concludes with a very realistic view of the other side of the same if/then offer. If the people would not listen, neither obey... well, then God threatened them with terror, consumption, the burning ague, sorrow of heart, failure in agricultural endeavors, defeat, cowardice, shame, fruitless prayers, wasted efforts, wild beasts, decreases in population, domestic danger, pestilence, poverty, hunger, cannibalism, death, rejection, desolation and national eviction.