In the English language, we have no end of phrases that are loaded with meaning, but are not meant to be taken literally. Think of “clear sailing,” or “stuck my foot in my mouth.” We have a shared cultural language of adages that achieves the same effects, from a classical “we who are about to die,” to Arnold Schwartzenegger’s “I’ll be back.” (In my family, being lovers of English wit, we have a soft-spot for “It’s not there.”)
The Torah does a similar thing, but its linguistic twists are self-referential. So, for example, the word “holy” is best understood by seeing how it is used in the text, from the burning bush to the major elements of the tabernacle.
The Torah, just like the English language, can use hyperbole to make a strong and specific point, which may not be intended literally. “Eye for an eye” is one well-known example, where the compensation is the market value of an eye (comparing a whole servant to a partially-blind one). But there are much more poetic example.
A mamzer [the product of an adulterous/incestuous relationship] shall not enter into the congregation of the LORD; to his tenth generation shall he not enter into the congregation of the LORD. (Deut. 23:2)
On the one hand, this seems like a very simple commandment. But on the other, it is highly problematic, especially for a religious faith that believes that people should be able to grow and change. How can someone be condemned because of the circumstances of their birth?
Here I think the Torah is actually making a profound point, which has little to do with counting generations.
If you count the lineage given in Genesis, there are ten generations from Adam to Noah. And then there are ten more generations from Noah to Avraham. And see how much changes: Adam’s world was unrecognizable from Noah’s – and Noah similarly inhabited a very different world than did Avraham. Every aspect of their respective eras, as described in the Torah, was radically and profoundly different from Adam to Noah, and then from Noah to Avraham.
A mamzer is the product of an “impossible” relationship in Jewish Law: the product or descendant of two people who could not, in law, possibly be married. If two siblings conceive, or a man impregnates a woman who is married to another, the baby is a mamzer. The definition is quite limited: for example, if two single (but unmarried) people procreate, or the baby is the result of an intermarriage, the baby is not a mamzer.
It may sound like legalistic distinctions, but there is a central, and major point: the kinds of actions that lead to a mamzer are far, far away from what is acceptable among Torah Jews. Distorting and abusing our creative powers to this extent is something that cannot be allowed “within the congregation of the Lord.”
Which explains why the Torah tells us that a mamzer cannot properly re-enter the Jewish people “to the tenth generation.” This kind of perversion is so unacceptable that the mamzer (and his/her descedants) need to be as far removed from the forbidden action, as Noah was from Adam, and as Avraham was from Noah. In other words, unless and until everything has changed, the product of such a relationship is not allowed to rejoin the Jewish people.
The Torah is using precisely the kind of linguistic shorthand that makes metaphors so powerful, and useful: just a few words trigger an avalanche of meaning.
Footnote: One might ask why it is the mamzer, and not the adults who created him/her, who are excluded from society. I think the answer is that Judaism is not just about thoughts or words or even deeds: the products of our deeds, the legacy that we create in this world and leave behind, are ultimately what matter most. Judaism is all about the fruits of our labors and loves.
Think of how it would feel to realize that your own actions have created a child who, by law, will be ostracized. We feel the pain of our children so much more than our own. And to complicate things still further, we realize that a mamzer is quite likely to despise his/her parents – which itself is another lesson that will haunt the parents for the rest of their days. The punishment fits the crime.