“Man is compared to a breath; his days are like a passing shadow”
(Tehillim 144:4)
Metzudat David says that a person’s days pass like a fleeting shadow, which does not remain for long in one spot. When the sun moves, the shadow moves, as well. This pasuk refers to Shaul Hamelech, who was honored and glorified. Eventually, he passed on and was no longer.
In Sha’arei Teshuvah, Rabbeinu Yonah (Sha’ar 2) writes that our Sages expound on the expression “like a passing shadow” in the following way: Man is not like the shadow of a tall tree or a high wall, but merely like the shadow of a flying bird. Man is obligated to consider his life in this world as a bird in flight, one moment here and the next moment, gone. One does not know when his last day on this earth will be. There is no reason to agonize over the morrow, for one never knows if he will live another day. As we are taught (Mishlei 27:1), “Do not boast about the morrow, for you do not know what a day may bring.”
“Everything has its season, and there is a time for everything under the heaven” (Kohelet 3:1).
Rashi expounds, “Everything has a set time when it will be.”
“A time to love and a time to hate; a time for war and a time for peace” (Kohelet 3:8)
The Ibn Ezra says, “Even love and hate are contingent on time.”
Man worries for money earned day by day, yet not for his life which fades away. Money helps not, he will learn. Nor will his days return.