This theory states that in order for society to run smoothly, we have to accept that there is a hierarchy.
Most societies have a hierarchy, which means that people in certain positions hold authority over the rest of us e.g. police officers, bouncers etc.
Authority is legitimate if it is agreed by society.
Most of us agree that this allows society to run smoothly.
We are willing to give up our independent behaviour and do things that someone in power tells us to do, because we TRUST them to exercise their authority properly.