What does Psalm 90:11 mean?
Moses had extensive experience with those who did not fear God as much as they should. That was the case both in His role in Israel's rescue from Egypt (Exodus 6:6) as well as their wandering in the desert (Deuteronomy 9:6–8). Here Moses wonders, rhetorically, who can know the power of God's anger and wrath, as a true fear of God demands?Sin invites God's anger, and in wrath He executes judgment. Knowledge of this fact should cause individuals to refrain from violating God's commands. The generation of Israelites that fell in the wilderness experienced God's anger and wrath. Would those Israelites have made the right decision and entered Canaan if they had correctly assessed the power of God's anger and wrath?
While Scripture communicates God's love and mercy, it also communicates His righteous anger and wrath. Sinning against a perfectly holy Creator necessarily incurs His judgment. And yet, because God loves sinners, He provides forgiveness for those who turn from sin and receive Jesus as their Savior. Romans 8:1 assures us there is no condemnation for those who are in Christ Jesus. However, those who spurn God's love and forgiveness revealed in Jesus must bear the eternal wrath of God (John 3:36; Revelation 20:10–15).
Psalm 90:11–17 calls on the Lord to teach His people to number their days and gain wisdom. Moses, the author, prays for mercy and joy. Also, he asks the Lord to prosper His servants' work. Other Scriptures emphasize God's compassion, the joy He gives, and the blessing He pours out on those who serve Him (Psalm 100:5; Proverbs 22:4). The books of Ezra and Nehemiah demonstrate the truth that God grants these gifts to those who honor Him, even if those gifts aren't always in the form of an easy, prosperous life.
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.