Two Scenes:
First, the Psalmist draws our attention to a hill upon which a farmer is lifting his wheat into the air. A wind is blowing and carries the chaff with it. The good seed falls to the ground.
Second, we see a strong tree - clearly having weathered the times yet the branches are filled with leaves and fruit.
Most people look at the "black and white" life pattern with disdain. We favor life in the blended zone and want the gray zone as a particularly acceptable pattern for life. Others like the dichotomized perspective of life - one for weekends and the other for business.
More... 40 Favorite Psalms
