What does Psalm 90 teach about the brevity of life?

In Psalm 90, Moses reflects on the brevity of human life by comparing it to grass, which flourishes in the morning and is cut down in the evening. Verse 4 states that a thousand years in God's sight are like a day that has just passed. This highlights the insignificance of our earthly existence in comparison to God's eternal nature, reminding us of the reality of mortality and the appointed return to dust, as expressed in Genesis 3:19. The psalm serves as a sober reminder to consider how we spend our days and to seek wisdom in our limited time on earth.