"As flies to wanton boys are we to the gods." Please give background to this quote in King Lear.

Gloucester speaks this line in Shakespeare's King Lear. 
It is a fairly profound line in a drama that is filled with many of them.  The sum total
of the line represents the relationship between individuals and the gods.  It reveals
how the forces of fate and predestination can be cruel, and how individuals have little
say, if any, about it.  In the end, the statement reflects the futility of human freedom
in the face of overwhelming odds and contexts.  Gloucester says these lines after
revelation about many elements. He understands his own folly, in supporting one son over
another, and grasps his own poor decision making, in believing the good one was bad and
the bad one was good.  He speaks from a position of having been blinded physically, but
possessing a restored sense of sight subjectively.  In the end, the comparison of human
beings to flies and the gods as impetuous, young boys helps to bring out the dynamic of
a world order where there is little structure or guidance.  There is only a condition of
servitude and lack of justice which governs it.