Derek Kidner writes: “Only Isaiah 40 can compare with [Psalm 90] for its presentation of God’s grandeur and eternity over against the frailty of man.” Walter Brueggemann calls it “one of the most magisterial of the psalms.” This is the only Psalm attributed in the book to Moses but it is perhaps fitting that his psalm begin book four since he is mentioned by name in four psalms of this section and most often in the final one, Psalm 106.
What prompted this prayer?
It is certainly, in the mind of Moses, the sins of Israel.
The poem begins with an exaltation of God and a comparison with the frailty of mankind (vss. 1-6). Their deplorable situation is due to the direct and disciplining hand of God (vss. 7-12) and here, Moses makes the first of three requests: Teach us to use our time wisely that our hearts might become wise. He requests this before he ever asks God to loose their punishments. Moses has no idea how long they will go on, but he wants God to use his power to make sure His people learn something about their condition and what caused it, that they might not repeat it.
The final section makes two more requests: First, that God will relent. “How much longer?” he asks, a recurring theme in the psalms (see 6:3; 13:1; 35:17 and especially 74:9), followed by the request for compassion, underscored by a reference to God’s “unfailing love.” If God doesn’t respond, Moses seems to be saying, it won’t square well with God’s reputed nature. The second request is that God will “establish the work of their hands.” I love the way John Goldingay puts it: “Grant that all the hard work we do in sowing and plowing, in building and planting, pays off rather than be a waste of time.” Whatever else they may be suffering, the menial and redundant tasks of day to day living must continue. The husband whose house has burned to the ground can’t spend his time sifting through the ashes. He must find clean clothes and go to work, coning home to ruin day after day until the home is rebuilt. Moses asks that God will at least make those times productive so that all is not lost. He’s not asking for great blessing. He’s just asking for normalcy.