Our situation on this earth seems strange. Every one of us appears here, involuntarily and uninvited, for a short stay, without knowing the why and the wherefore. In our daily lives we feel only that man is here for the sake of others, for those whom we love and for many other beings whose fate is connected with our own.

[Seltsam erscheint unsere Lage auf dieser Erde. Jeder von uns erscheint da unfreiwillig und ungebeten zu kurzem Aufenthalt, ohne zu wissen, warum und wozu. Im täglichen Leben fühlen wir nur, dass der Mensch um anderer willen da ist, solcher, die wir lieben, und zahlreicher anderer, ihm Schicksalsverbundener Wesen.]

Albert Einstein (1879–1955) German-American physicist

Essay (1932-09), “My Credo [Mein Glaubensbekenntnis]”
    (Source)

(Source (German); (Audio @ 0:37)).

Einstein crafted and recrafted his credo multiple times in this period, and specifics are often muddled by differing translations and by his reuse of certain phrases in later writing. The (1930-10), "What I Believe," Forum and Century version appears to be the earliest iteration:

Strange is our situation here upon earth. Each of us comes for a short visit, not knowing why, yet sometimes seeming to divine a purpose. From the standpoint of daily life, however, there is one thing we do know: that man is here for the sake of other men -- above all for those whose smiles and well-being our own happiness depends, and also for the countless unknown souls with whose fate we are connected by a bond of sympathy.

Other translations:

What an extraordinary situation is that of us mortals! Each of us is here for a brief sojour; for what purpose he knowsnot, though he sometimes thinks he feels it. But from the point of view of daily life, without going deeper, we exist for our fellowmen -- in the first place for those on whose smiles and welfare all our happiness depends, and next for all those unknown to us personally with whose destinies we are bound up by the tie of sympathy.

— "The World As I See It [Mein Weltbild]" [tr. Harris (1934)]

How strange is the lot of us mortals! Each of us is here for a brief sojourn; for what purpose he knows not, though he sometimes thinks he senses it. But without deeper reflection one knows from daily life that one exists for other people -- first of all for those upon whose smiles and well-being our own happiness is wholly dependent, and then for the many, unknown to us, to whose destinies we are bound by the ties of sympathy.

— "The World As I See It [Mein Weltbild]" [tr. Bargmann (1954)]