In contrast to the spontaneous prose prayers found in biblical narratives (see Miller, They Cried to the Lord, Appendix 1), the Psalms are tightly woven poetic compositions. Even prayer psalms reflecting life or death distresses (such as Psa 13 and 22) exhibit intricate literary echoes and structures. While their references to singing imply oral performance, their intricate wording implies that psalms were literary compositions, not spontaneous ad hoc cries of help or praise.

Wisdom psalms reflect the same wisdom tradition known from Proverbs, Job, and Ecclesiastes. Rather than addressing God directly in worship, they incorporate literary forms characteristic of the wise sages. They either teach wise living, or probe life’s anomalies.

The Torah psalms, Psa 1, 19:7–14, and 119, uniquely refer to “the law of the Lord.” While “torah” is usually translated “law,” the word means “instruction,” and thus can include instruction of any form, such as laws, narratives, and poems.

This psalm contrasts the righteous person who because of his or her behavior experiences blessing in life with the unrighteous whose ungodly conduct yields the fruit of sorrow and destruction.

Counsel, way and seat (or ‘assembly’, or ‘dwelling’) draw attention to the realms of thinking, behaving and belonging, in which a person’s fundamental choice of allegiance is made and carried through;

Yet certainly the three complete phrases show three aspects, indeed three degrees, of departure from God, by portraying conformity to this world at three different levels: accepting its advice, being party to its ways, and adopting the most fatal of its attitudes

The law of the Lord stands opposed to ‘the counsel of the wicked’ (1), to which it is ultimately the only answer. The psalm is content to develop this one theme, implying that whatever really shapes a man’s thinking shapes his life.

Law (tôrâ) basically means ‘direction’ or ‘instruction’; it can be confined to a single command, or can extend, as here, to Scripture as a whole.

The phrase its fruit in its season emphasizes both the distinctiveness and the quiet growth of the product; for the tree is no mere channel, piping the water unchanged from one place to another, but a living organism which absorbs it, to produce in due course something new and delightful, proper to its kind and to its time. The promised immunity of the leaf from withering is not independence of the rhythm of the seasons (cf. the preceding line, and see on 31:15), but freedom from the crippling damage of drought (cf. Jer. 17:8b).

The simile in verse 4 goes as far beyond Jeremiah’s contrast of fruitful tree and desert shrub (Jer. 17:6) as the judgment (5) goes beyond ordinary calamities. And it emphasizes more explicitly what a man is than what he sees and feels (cf. Jer. 17:6a, 8b); hence the unsparing conclusion. Chaff is, in such a setting, the ultimate in what is rootless, weightless (cf. the ‘vain and light persons’ of Judg. 9:4, AV) and useless. The figure is that of winnowing, in which the threshed corn is tossed up for the husks and fragments of straw to blow away, leaving behind only the grain.

The end has nothing arbitrary about it: note the irreducible contrasts in this verse, whose opening Therefore leads inexorably out of what these men have chosen to be (4). Before the Judge they will have, in our similar phrase, not a leg to stand on, and among his people no place. These two aspects of judgment, collapse and expulsion, are portrayed again with immense power in Isaiah 2:10–21.

To ‘know’ is more than to be informed (as in 139:1–6): it includes to care about, as in 31:7 (Heb. 8), and to own or identify oneself with (cf. Prov. 3:6). To perish is used in many senses: here for instance of a road or course that comes to nothing or to ruin; elsewhere of hopes or plans frustrated (e.g. 112:10; Prov. 11:7), of creatures that get lost (119:176), and of men and achievements that come to grief (2:11; 9:6). The New Testament brings to light the eternal implications which are already contained in it (e.g. John 3:16).

So the two ways, and there is no third, part for ever.