Thank you to Dalpreet Saluja
In short, Sikhs do not cut their hair because we believe that to be one with God you must maintain the form that he gave you. This includes not cutting your hair or shaving. Hair is one of the many gifts from God, and we should respect it. For this reason, Sikh men have long beards and long hair and many Sikh woman do not shave other parts of their body. If you look to other religions, many depictions of prominent figures have long hair – like Jesus and Moses. One explanation is because of the purity these individuals represent, and unshorn hair is one way of illustrating their purity. Another reason for our unshorn hair is that it is one of the 5 articles of faith for Sikhs called Kesh (the others being Kanga [a comb], Kachha [underwear or briefs], Kirpan [sword] and Kara [steel bracelet]). Together, these 5 articles of faith form the identity of all Sikhs as established by the 10th Guru of the Sikhs, Guru Gobind Singh Ji. Like articles of faith for other religions – Yumulke for Orthodox Jews, for example – these define our existence as Sikhs.