One great power of sin is that it blinds men so that they do not recognize its true character.
-- Andrew Murray
 This seems quite true, doesn't it?  In many respects, our sin(s) dull our sensitivity to God...our awareness of Him, even our interest in His ways.  It blinds us, so that we don't see Him as clearly as we otherwise might.  Perhaps this is why our prayers and songs acknowledge the phrase, 'Open our eyes, Lord....'  It is as much confession, as desire.
 There's a day that's drawing near 
When this darkness breaks to light 
And the shadows disappear 
And my faith shall be my eyes
-- Chris Tomlin
...more on blindness and sin.
 
