https://craigsbooks.wordpress.com/2016/11/11/when-you-can-see-no-light-at-the-end-of-the-tunnel-light-your-own-candle-and-let-your-light-illuminate-the-world-like-the-radiance-from-a-window-at-midnight-thats-a-metap/
“When you can see no light at the end of the tunnel, light your own candle and let your light illuminate the world, like the radiance from a window at midnight.” That’s a metaphor, BTW