Carl Sandburg: Timing

Remembrance Rock (1948), Ch. 2, p. 7
Context: A baby is God's opinion that life should go on. A book that does nothing to you is dead. A baby, whether it does anything to you, represents life. If a bad fire should break out in this house and I had my choice of saving the library or the babies, I would save what is alive. Never will a time come when the most marvelous recent invention is as marvelous as a newborn baby. The finest of our precision watches, the most super-colossal of our supercargo plants, don't compare with a newborn baby in the number and ingenuity of coils and springs, in the flow and change of chemical solutions, in timing devices and interrelated parts that are irreplaceable. A baby is very modern. Yet it is also the oldest of the ancients. A baby doesn't know he is a hoary and venerable antique — but he is. Before man learned how to make an alphabet, how to make a wheel, how to make a fire, he knew how to make a baby — with the great help of woman, and his God and Maker.

"The People Will Live On" (1936)

Variant: Life is an onion - you peel it year by year and sometimes cry.
Source: Remembrance Rock

Variant: Time is the most valuable coin in your life. You and you alone will determine how that coin will be spent. Be careful that you do not let other people spend it for you.

Quoted as Sandburg in Stop Whining! Start Selling!: Profit-Producing Strategies for Explosive Sales Results (2003) by Jeff Blackman, but without citation of original source; this is elsewhere attributed to Antoine de Saint Exupéry, but also with no original sources cited.
Disputed

"Washington Monument by Night" in Slabs of the Sunburnt West (1922)