Sikh Gurus devoted their lives for the benefit of humanity and some even sacrificed their lives looking after the welfare of others. The Guru Granth Sahib says
Within this world take the opportunity for self less service to others; Then in divine abode we get the chance to be; the Eternal will embrace you.
Seva or selfless service is at the core of being a Sikh; to give without seeking reward or recognition and know that all seva is known to and appreciated by the Eternal. Seva can also be donation of one’s organ to another. There are no taboos attached to organ donation in Sikhi nor is there a requirement that a body should have all its organs intact at or after death. According to Sikhi the soul migrates in a perpetual cycle of rebirth but the physical body is only a vassal in its long journey, left behind each time and dissolved into the elements The Guru Granth Sahib says in Asaa Mahala 5:
That time, which the mortal does not wish for, eventually comes. Without the Eternal's order the understanding of mortality is never understood. The body is consumed by water, fire and earth. But the soul is neither young nor old, O human, thus it is the soul and not the body which continues its journey.
The Sikh religion teaches that life continues after death in the soul, and not the physical body. The last act of giving and helping others through organ donation is both consistent with and in the spirit of Sikh teachings.
Donating one’s organ to another so that the person may live is one of the greatest gifts and ultimate seva to human kind and hence to Satguru says
Through selfless service, eternal peace is obtained. The Gurumukhi is absorbed in intuitive peace.
Donation without reward is one of the characteristics of a Guru’s Sikhs. The life of Gurumukhi is useful because by their natural temperament they are donors. And why not donate an organ so another can live?