light at the end of the tunnel 的詞源

比喻義，「長期追尋的目標或結局即將達成的希望之兆」，自1879年起使用。字面意義，指鐵路隧道，早在1833年。

Sometimes we have an experience in life that seems like walking through a long, dark tunnel. ... We can only fix our eyes on the bright light at the end of the tunnel, and we comfort ourselves with the thought that every step we take brings us nearer to the joy and the rest that lies at the end of the way. ["Trusting God in the Dark," sermon printed in several U.S. newspapers late 1881, credited to Presbyterian minister Theodore L. Cuyler]

有時我們在生活中會有一種經歷，彷彿是在穿越一條漫長而黑暗的隧道。……我們只能將目光固定在隧道盡頭的明亮光芒上，並安慰自己每一步都使我們更接近那份喜悅與安息，這些都在道路的盡頭。[「在黑暗中信靠上帝」，1881年底在幾本美國報紙上刊登的講道，歸功於長老會牧師西奧多·L·凱勒]