When God presented Isaiah with an opportunity to be His messenger, Isaiah jumped at the opportunity.  He didn't give a list of reasons why God should pick someone else (as did Gideon), nor did he share his long list of short-comings.  Several years ago I knew that God was asking me to do something, but because of fear, I wasn't sure I wanted to do it.  Isaiah exemplifies the importance of doing as God requests when He requests it – with alacrity.  Alacrity means cheerful readiness.  Are you ready when God asks?  If you don't do it, then who will?  If not you, then who?  Consider it a privilege and an opportunity that God chooses to include us in what He's doing in the world.