John Piper's testimony & story of 30 years of ministry: click here
His passion for preaching and spurring fellow believers on to joy in their salvation was a goal he had 30 years ago. He still, even today, continues to set his sights on this goal.
His candidate sermon is just as powerful as his preaching today, although his voice pitch is a little different, the passion and the sincerity is still there.
Listen to his candidate sermon: click here