Complaining is evidence of being discontent with our circumstances.  Not long ago, I remember whining to God in prayer about a problem.  Then God nailed me.  Circumstances are not usually controlled by us but by others and God.  Since God is all powerful and promises to work all things for good, then when we complain, what we are really saying is, "God, I'm not happy with the hand you've dealt me today and I'm not willing to trust you with it because I don't think you can handle it."  Most of us would never think of saying that to God, but that is the message our actions send.  Let's commit today to take captive our complaints and trust God with whatever circumstances we face.