Deuteronomy 11:13-15 ASV and Matthew 6:31-34 ASV

This is quite the promise in Deuteronomy 11 - if the people love the Lord God and serve him with all their heart and with all their soul— then He will send rain in its season, will provide grass for the cattle, and food to eat that they will be satisfied. If there is drought in the land, is it reasonable to think that the if the people part of the bargain is not being upheld?

Lest we think this is only for the people of Israel, fast forward to Matthew 6:31-34, where Jesus teaches his followers not to be anxious about what to eat, drink or wear. He tells us the Father knows we need all those things, and instructs us to "seek first his kingdom, and his righteousness; and all these things shall be added". This would seem to be a similar "If {...}, then {...}" scenario.

I wonder if the series of disasters of our day, starting with the financial meltdown and most recently throwing in a possible Swine Flu epidemic, aren't happening because we have disregarded the "if" part. In such case, Deuteronomy 11 goes on to tell us that nothing will grow in our fields, and we will die and disappear from the good land the Lord had given us. Hmmm...