Sikh Gurus introduced Sikhs as a Saint Soldier. This in turn teaches us the purpose of life. Sikhs should lead their life playing the roles of both the Saints and Soldiers. Here, soldier doesn't really mean that you have to fight in wars, battles or fight with other humans. The Sikh soldiers were, basically, assigned the task to protect humanity and fought for the exploited humans.
The concept of Soldier in a broader prospective could be thought of as a person who fights this battle of life which has been bestowed upon him by the Almighty. It means that a person should be successful in his worldly affairs. He should be a leader wherever he goes. For that, we got a unique identity, which we maintain by keeping our Kesh (hair) and wearing a turban. Sikhs should stand out in the crowd and be a winner in this battle of life.
A Sikh should also be a Saint. He should remember God with every brath of his life. He should always lead a life which should be full of honesty and integrity. He should never harm any other human. A person doesn't becomes a Saint by self-declaration but is considered one by good moral practices, which are expected by every human being.
Thus, a true Gursikh is the one who is 'A Saint Soldier'. He should have both saintly qualities and should be able to defend himself in this battle of life. Now, how can you defend yourself in this battle of life? Surely, by doing good deeds and remembering the name of the Creator Lord, who Himself blesses us the gift of His Name.
The concept of Saint-Soldier was first started by Guru Hargobind Sahib Ji who wore two swords of Miri - n - Piri. Miri is the worldly sword (sword worn by a king, commander etc) and Piri signifies spirituality. The existence of both swords together signifies the importance of the dual roles of a human being in this invaluable gift of life.
Another example which signifies the concept of a Saint-Soldier is the coexistence of both Sri Akal-Takhat Sahib and Sri Harmandir Sahib (Golden Temple) together in the same complex. Harmandir Sahib is the centre of Sikh spirituality, while Akal Takhat Sahib is the temporal throne of the Sikhs. A point worth noting, here, is that when you look at Sri Harmandir Sahib from Sri Akal Takhat Sahib, you can clearly view Harmandir Sahib. While, if you try to view the Akal Takhat from Golden Temple, you won't be able to view it. This signifies that the search for spiritual grace should always lead. When you are trying to remember God you should forget all worldly aspects, but when you are fulfilling your temporal needs always keep the True Lord's Name in your mind. Never ever forget the Name of the One Lord from your mind.
Further, Guru Gobind Singh Ji gave us the title of a Singh. Singh, which literary means a Lion, signifies the the lion as the King of the jungle. It emphasizes that a Singh is born as a King and should be a leader in whatever he does. A Singh should be a role-model for this human race and should always protect the dignity of his fellow humans.
A Sikh should consider God as the supreme commander of this world and always accept His will as the Supreme. Lets pray to Lord that he always helps us to be on the right path and blesses us to always remember His Name.
P.S.: Most thoughts depicted in this article are my own interpretation of the message given by the Gurus. As it is said, to err is human, my interpretation may be a bit incorrect. Your suggestions and criticisms are most welcome.
Please do correct me if I'm wrong. I would appreciate if someone could validate (invalidate too, if they are wrong) these thoughts by referring to Gurbani.