Jesus entered the temple area and drove out all who were buying and selling there. He overturned the tables of the money changers and the benches of those selling doves. "It is written," he said to them, "'My house will be called a house of prayer,' but you are making it a 'den of robbers.'" Matthew 21:12-13
The temple complex was supposed to be dedicated to the worship of God, but the money changers were using it to engage in commerce. Too often we take was is supposed to be dedicated to God and allow it to be dominated instead by the desires and lusts of mankind.
The Christian's heart is the temple of the Holy Spirit. It is supposed to be dedicated to God. What type of things are you allowing to enter in? Jesus calls mere thoughts sinful because He knows that we indulge in thoughts. It is not just that we see an attractive person walk by. Where do you allow your mind to wander afterwards? It is not just seeing your neighbor's new 30 foot boat. What fantasies do you allow yourself to indulge in afterwards?
Is God still first in your heart or do you allow lust, the love of money, or any other non-Biblical desire to take His place?