At some point, most Jedi become Jedi Masters. Either through taking on a pupil or pupils as Padawan? or through the virtue of their accomplishment, they become recognized by the Jedi Council and/or their peers as a Master. The title brings more responsibilities as they are expected to be able to speak on behalf of the entire Jedi Order. Technically the highest rank within the order, the only way to hold more clout is through experience or by joining the Jedi Council.