It is not appropriate to grieve in an hour of joy.. You all weep, but is there any real cause for grief? We should look upon a sage as a person escaped from a burning mansion... it does not matter whether I am here or not; salvation does not depend upon me but upon practising the Dharma, just as a cure depends not upon the doctor but upon taking the medicine... My time has come, my work is done... Everything eventually comes to an end, even if it should last for an aeon. The time of parting is bound to come one day. I have done what I could for myself and others, and to remain longer would be without purpose. I have trained all whom I could train. My teachings shall last for many generations, so do not be disturbed. Recognize that all that lives is subject to the laws of impermanence, and strive for eternal wisdom. When the light of knowledge dispels ignorance, when the world is seen as without substance, the end of life is seen as peace and as a cure to a disease. Everything that exists is bound to perish. Be therefore mindful of your salvation. The time of my passing has come.
Buddha's final sermon