Therefore they will be like the morning cloud, And like the dew that passes away early, Like the chaff that is driven with the whirlwind out of the threshing floor, And like the smoke out of the chimney.
"As the chaff that is driven ..." The chaff was made a symbol of the lost in the New Testament  (Matthew 3:12).  In the ancient custom of threshing grain, the threshing-floors were usually placed on high elevations readily accessible to the wind.  The chaff was absolutely worthless, fit for any disposal of it that was available.  The application of such similies as these to Israel indicated their approaching demise as a political entity upon earth.