As for man, his days are as grass: as a flower of the field, so he flourisheth.
-Our grass-like frailty and mortality would cause us to despair, but that we have sure hope in Yahweh's everlasting mercy to those that fear Him, as well those of the latest generation as those of the earliest. Compare Moses' words, Psalms 90:1-5, from which this passage is derived. Compare a similar contrast between man's grass-like frailty and God's eternal word, Isaiah 40:6-8. Here it is God's everlasting mercy.
Verse 15. As for man, his days are as grass. "Man" - literally, mortal and miserable man: Hebrew, 'ªnowsh (H582), from a root х 'aanash (H605)], to be desperately diseased (Buxtorf). Seth so named his son (Genesis 4:26), from the humanly-incurable misery into which man had fallen by sin. So Psalms 8:4. (See the note there); Psalms 37:2.
As the flower of the field, so he flourisheth. His flourishing or vitality is of as short duration (Psalms 90:5-6; Job 14:1-2).
Verse 16. For the wind passeth over it, and it is gone - the scorching east wind (Genesis 41:6; Genesis 41:23; Jonah 4:8).
And the place thereof - namely, of the flower.
Shall know it no more - (Job 7:10; Job 20:9).
Verse 17. But the mercy of the Lord is from everlasting to everlasting upon them that fear him. "Upon them" - i:e., protecting them from above, and coming upon them in blessings. Thrice the words of limitation, "them that fear him," are repeated as a warning against transgressors presumptuously taking to themselves this promise, which does not belong to them (Psalms 103:11; Psalms 103:13; Psalms 103:17).
And his righteousness unto children's children - (Exodus 20:6.) God's righteousness consists not in His rewarding us according to our strict merits, but in His showing faithfulness to His own character and to His promises (Psalms 103:18) to them that sincerely seek Him. Alike to the fathers of Israel (Psalms 103:7) and to the remotest children (Luke 1:72-74; Acts 2:39). The ultimate ground of God's being righteous in showing mercy is the law-fulfilling righteousness of Messiah.
Verse 18. To such as keep his covenant. Deuteronomy 7:9; Deuteronomy 7:11 is referred to here, and in Psalms 25:10.
And to those that remember his commandments - (cf. "forget not," Psalms 103:2.) He "remembereth" us (Psalms 103:14) when we "remember" Him, "His benefits," and "His commandments."