There are five things that go with the Sikh tradition, uncut hair (covered in a turban), a comb, a dagger, a bracelet, and a specific style of clothes. These are all the five symbols of Sikh tradition. They should be respected because the Guru has asked you to do these things, to make an identity for you.
In those days, every family gave one boy, most probably, their first son, to the Guru, and the Guru trained them all. This is what happened to everybody’s son. So, they were all trained to act like soldiers, as well as go inwards. To pray and to act, and to protect the dharma.