Dora Bas Rivka Silver O'H
Psalm 90 is the first Psalm in the fourth "book" of Psalms. It is also the first in a series of Psalms attributed to Moses.
Moses says that G-d has always given the Jewish people a safe refuge in times of danger. G-d was always G-d, even before He created and populated the world. He will always continue to be G-d, even after the world passes away.
G-d can reduce an arrogant person until he realizes that he is nothing, and He urges people to return to Him. To G-d, a thousand years are like a day gone by. A person's entire life is no more than a few hours to G-d. Our days may seem slow to us, but they rush past G-d like the waters of a river. A person's whole existence is no more permanent than a dream. We are like flowers that bloom, then wither away without a trace.
We sinned and angered G-d, with the result that we are now in danger in exile. Our errors and sins are laid out before G-d. Our lives are insignificant. How long does a person live? 70 years? 80 if he's particularly robust? And what do we have to show for it? Nothing but trouble! And then we leave nothing behind.
No one can know the extent of G-d's anger. Our lives are so short, we can only see a tiny piece of the puzzle. Hopefully, we learn something from it!
How long will G-d be angry with us? We wait for the daybreak of His kindness, for which we will eternally praise Him. May we enjoy as many good days as those we suffered in exile. May G-d's actions be seen by us and may they be obvious to our descendants. May His pleasantness be upon us and may He firmly establish the work of our hands.
This familiar Psalm is said on Shabbos mornings and the concluding verses (Vayehi Noam) are also said at the conclusion of Shabbos.