He addresses the fact the church is using people to gain money by the selling of indulgences (little prices off paper saying that either you or some one you love can get out of hell). The churches philosophy was: you can go to heaven only through the church. Luther's philosophy: faith and faith alone. That means if you have faith you can go to heaven. His thesis basically told EVERYONE that what the church was doing wrong. That they wetter lying to the people. Hope this helps :)