Man is like to vanity: his days are as a shadow that passes away.
Read Chapter 144
Augustine of Hippo
5. "Man is made like unto vanity: his days pass away like a shadow" (ver. 4). What vanity? Time, which passeth on, and floweth by. For this "vanity" is said in comparison of the Truth, which ever abideth, and never faileth: for it too is a work of His Hand, in its degree. "For," as it is written, "God filled the earth with His good things." What is "His"? That accord with Him. But all these things, being earthly, fleeting, transitory, if they be compared to that Truth, where it is said, "I Am That I Am,"(3 ) all this which passeth away is called "vanity." For through time it vanisheth, like stroke into the air. And why should I say more than that which the Apostle James said, willing to bring down proud men to humility, "What is," saith he, "your life? It is even a vapour, which appeareth for a little time, and then vanisheth away." ...Work then, though it be in the night, with thine hands, that is, by good works seek God, before the day come which shall gladden thee, lest the day come...
Vanity. Hebrew hebel, "nothing, a vapour", Ecclesiastes i. 1., and James iv. 15. (Haydock)
Our lives resemble a shadow, which is the less distinct, the more it increases. (Berthier)
As it cannot subsist of itself, so neither can man without God. (Worthington)