Seneca · On grief for lost friends
Letters 63.16
Let us therefore reflect, my beloved Lucilius, that we shall soon come to the goal which this friend, to our own sorrow, has reached. And perhaps, if only the tale told by wise men is true and there is a bourne to welcome us, then he whom we think we have lost has only been sent on ahead. Farewell.
Seneca, Letters to Lucilius 63.16, translated by Richard Mott Gummere