The concept of Karsewa dates back to the times of Sikh Guru Sahibs - who took keen interest in founding and developing new towns and construction activities. Guru Nanak Dev Ji founded Kartarpur town. Sub sequently towns of Khadoor Sahib, Goindwal, Amritsar, Tarn Taran, Akal Takht and Kirat Pur Sahib and Anand Pur Sahib were got constructed and developed by Guru Angad Dev Ji, Guru Amar Dass Ji, Guru Ram Dass Ji, Guru Arjan Dev Ji, Guru Har Gobind Sahib Ji and Guru Teg Bahadur Sahib Ji respectively. This tradition of building activities was carried forward throughout various periods of Sikh history.
Sikh Religion is full with the sense of selfless-service. Be it be in the sphere of Social works, humanity or construction of Gurudwaras.
If you have visited the Gurudwaras of Delhi or Punjab in recent times you could not have avoided noticing the selfless devotion and dedication with which the construction work is taken up by devotees; unmindful of their status, caste or creed. This Voluntary labour or KAR SEWA by devotees has palyed a major role in building of temples of religious belief (Gurudwaras) right from the early stages of Sikhism.

Karsewa: Baba Harbans Singh Ji Karsewa Wale
Baba Baghel Singh Ji, who conquered Delhi with his army magnanimously returned the throne to moghal emperor,because he had called the queen as sister. But as a true servant of Panth , he asked only for the reconstruction of all the historical Gurudwaras of Delhi which had been converted into Mosques.