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For death and life, in ceaseless strife, Beat wild on this world's shore, And all our calm is in that balm— Not lost but gone before.

"Not Lost but Gone Before" (ca. 1850). Burton E. Stevenson, Home Book of Quotations, and the Oxford Dictionary of Quotations trace "Not lost, but gone before" and similar expressions to Seneca, St. Cyprian, and Matthew Henry.
For death and life, in ceaseless strife, Beat wild on this world's shore, And all our calm is in that balm— Not lost but gone before.