Wisdom and proverbial literature was a leading genre of the ANE. Much of the OT, and parts of the NT, fall into this category. (One of the best-known examples outside the Bible is the Egyptian Wisdom of Amenomope.) Wisdom literature was (and still is) characterized by language of exclusivity. This is partially attributable to the fact that wisdom/proverbial literature was intended to be short, pithy, and easily memorized.
Our modern literature of this type --- for example, the maxims in Poor Richard's Almanac --- can be described similarly. The wisdom genre has changed little over the years from a functional perspective.
Because of these characteristics of proverbial and wisdom literature, the genre has a high rhetorical function and cannot be read as though it were absolute. Much of what is written in the OT, and a good deal in the NT, is subject to these constraints.
To use modern examples, consider these maxims, taken from the Random House Dictionary of Popular Proverbs and Sayings:
Skeptical conceptions of genre-contexts are revealed in this comment from a popular Skeptical newsletter. In response to a reader who noted the less than absolute nature of language in a passage in Ecclesiates (though without reference to proverbial literature), it was offered:
The Bible is a kind of contract. What do you think an opposing attorney would say to you if your client signed a contract in which the final clause said it was to be permanent and you said your client only meant a couple of years? You and I both know he would have a field day. That's what would happen. If your kind of textual alteration were permitted, you'd all but destroy the Bible's believability. How would you know what is to be taken at face value and what is to be interpreted according to the expediency you're proposing? And who makes that determination?
The answer to the last "who" is: "Scholars who have studied ancient literature and understand its context and purpose". It is wrong to say that the Bible is a "kind of contract." Deuteronomy is, but the Bible as a whole encompasses a wide variety of ancient genres.
Our point: Material in the Bible that belongs in the proverbial/wisdom genre cannot be read absolutely and used to claim error and/or contradiction.