What does Psalm 90:5 mean?
Human life is so brief that it resembles a dream and short-lived grass. God sweeps humans into eternity as suddenly as a flood overtakes everything in its path and washes it away. This imagery continues Moses' depiction of human frailty (Psalm 90:3–4).Jesus described two kinds of lives, using the metaphor of buildings (Matthew 7:24–27). One is built on sand, the other on a rock. A flood knocks down the house—the life—built on sand and sweeps it away, but it does not demolish the life built on a rock (Jesus' Word). That life stands firm. When an individual's life ends, God sweeps him into eternity. The life built on sand—anything except Jesus, the Rock of Ages (Isaiah 26:4)—will not withstand God's judgment, but the life built on the Rock of Ages will stand throughout eternity. It is of the utmost importance, therefore, to trust in the Savior. There is no security in wealth, fame, popularity, or any relationship except a personal relationship with Jesus Christ. Jesus asked a significant question: "For what does it profit a man to gain the whole world and forfeit his soul?" (Mark 8:36).
Psalm 90:3–10 reflects on life's brevity and God's wrath. Psalm 8:4 raises the question of man's status, and James 4:14 describes life as finite and fleeting. Numbers 14:33–35 spells out God's judgment on the Israelites for refusing His call to enter Canaan.
Psalm 90, likely the oldest psalm, opens with Moses addressing God as eternal and Israel's dwelling place, but quickly shifts to an acknowledgement of man's brief life on earth. Our iniquity is the reason God directs His wrath at us. In most cases, a person can expect to live somewhere around 70 or 80 years, barring disease or misfortune. Short or long, life is full of toil and trouble. In view of life's brevity, Moses asks the Lord to fill His people with wisdom. He also asks the Lord to reveal His work, demonstrate His power, grant His favor, and make Israel's labor successful.