The idea of immortality, that like a sea has ebbed and flowed in the human heart, with its countless waves of hope and fear, beating against the shores and rocks of time and fate, was not born of any book, nor of any creed, nor of any religion. It was born of human affection, and it will continue to ebb and flow beneath the mists and clouds of doubt and darkness as long as love kisses the lips of death. It is the rainbow — Hope shining upon the tears of grief.

Robert Green Ingersoll (1833-1899) American lawyer, freethinker, orator

Lecture (1877-06-23), “The Ghosts,” Carson Theater, Carson City, Nevada
    (Source)

Collected in The Ghosts, and Other Lectures (1878)