I noted earlier that there is evidence of editing in biblical books, and how that should be no surprise. Biblical books classified as wisdom literature lend themselves to that sort of thing more naturally than others.
For example, Psalm 72 tells readers matter-of-factly, “The prayers of David, the son of Jesse, are ended.” The only problem with that statement is that it isn’t true. There are many psalms of David that follow Psalm 72. The superscriptions of several psalms make this quite clear (e.g., Pss. 86; 101; 103; 108; 109; 110; 139; 140).
The statement in Psalm 72 is a classic marker of editorial activity. What we call the book of Psalms is actually five books. Many study Bibles will mark off the books with Roman numerals. “Book III” of the Psalms begins with Psalm 73. That makes it obvious that the comment in Psalm 72:20, the last verse of that psalm, was at one time the end of the psalms—which is what the verse says. As more psalms were collected and added to form Books III, IV, and V, the statement in Psalm 72:20 was rendered invalid yet allowed to remain in the text out of respect for the sacred nature of the material. The endings of Books I, III, and IV all end with a doxology, something to the effect of “blessed be the LORD, Amen and Amen.”
Proverbs also bears the marks of incremental collecting and editing. While we tend to think of Solomon as the author of the book, he is actually one of several figures credited with proverbs by the superscriptions within the book. Solomon is specifically credited with Proverbs 1–22, but the book contains material written by Agur son of Jakeh (Prov. 30:1–14) and Lemuel (Prov. 31:1–9). Much of the book is not attributed to anyone specific but labeled simply “words of the wise” (Prov. 22–24). Proverbs 25–29 are also apparently from Solomon but were “transcribed by the men of Hezekiah, king of Judah” (Prov. 25:1), who lived long after Solomon.
These sorts of indicators have two points of importance. First, they ought to make us more alert to the original context of a psalm or proverb. Sometimes a clear association with someone like David or Solomon is possible, allowing us to situate the content in a rough time frame. But in many instances, this isn’t obtainable, so we ought not relate that psalm or proverb to a specific person or situation for interpretation. Second, they are visible testimony to how inspiration really worked—over time and through the use of human hands. Knowing that helps us avoid bizarre ideas about how we got the Bible and helps us answer “difficulties” we encounter in the text, like the statement of Psalm 72:20.