A Commentary, Critical, Practical, and Explanatory on the Old and New Testaments, by Robert Jamieson, A.R. Fausset and David Brown  at sacred-texts.com
psa 90:1Contrasting man's frailty with God's eternity, the writer mourns over it as the punishment of sin, and prays for a return of the divine favor. A Prayer [mainly such] of Moses the man of God-- (Deu 33:1; Jos 14:6); as such he wrote this (see on Psa 18:1, title, and Psa 36:1, title). (Psa. 90:1-17)
dwelling-place--home (compare Eze 11:16), as a refuge (Deu 33:27).
psa 90:2brought forth [and] formed--both express the idea of production by birth.
psa 90:3to destruction--literally, "even to dust" (Gen 3:19), which is partly quoted in the last clause.
psa 90:4Even were our days now a thousand years, as Adam's, our life would be but a moment in God's sight (Pe2 3:8).
a watch--or, third part of a night (compare Exo 14:24).
psa 90:5Life is like grass, which, though changing under the influence of the night's dew, and flourishing in the morning, is soon cut down and withereth (Psa 103:15; Pe1 1:24).
psa 90:7For--A reason, this is the infliction of God's wrath.
troubled--literally, "confounded by terror" (Psa 2:5). Death is by sin (Rom 5:12). Though "secret," the light of God's countenance, as a candle, will bring sin to view (Pro 20:27; Co1 4:5).
psa 90:9are passed--literally, "turn," as to depart (Jer 6:4).
as a tale--literally, "a thought," or, "a sigh" (Eze 2:10).
psa 90:10Moses' life was an exception (Deu 34:7).
it is . . . cut off--or, "driven," as is said of the quails in using the same word (Num 11:31). In view of this certain and speedy end, life is full of sorrow.
psa 90:11The whole verse may be read as a question implying the negative, "No one knows what Thy anger can do, and what Thy wrath is, estimated by a true piety."
psa 90:12This he prays we may know or understand, so as properly to number or appreciate the shortness of our days, that we may be wise.
psa 90:13(Compare Psa 13:2).
let it repent--a strong figure, as in Exo 32:12, imploring a change in His dealings.
psa 90:15As have been our sorrows, so let our joys be great and long.
psa 90:16thy work--or, providential acts.
thy glory-- (Psa 8:5; Psa 45:3), the honor accruing from Thy work of mercy to us.
psa 90:17let the beauty--or sum of His gracious acts, in their harmony, be illustrated in us, and favor our enterprise.