The secret of karma yoga which is to perform actions without any fruitive desires is taught by Lord Krishna in the Bhagavad-Gita.
Swami VivekanandaThe only religion that ought to be taught is the religion of fearlessness. Either in this world or in the world of religion, it is true that fear is the sure cause of degradation and sin. It is fear that brings misery, fear that brings death, fear that breeds evil. And what causes fear? Ignorance of our own nature.
Swami Vivekananda"If you die, you get to heaven; and if you win, you enjoy the earth" (Gita). Even if you die in this attempt, well and good, many will take up the work, following your example. And if you succeed, you will live a life of great opulence.
Swami Vivekananda