Temple Cleansing (Matthew 21:12-17)

Our Lord arrives in Jerusalem with a remarkable reception.  The people praise him as the Lord he is, they throw down their cloaks, and it seems that Christ is able to take the city by storm.  However, Christ runs through the temple overturning tables, and driving people out of the temple.  Why does Christ react this way?  What does the temple tell us about the state of God’s people in this time?