אמ בחקתי, תלכו. ואת מצותי תשמרו, ועשיתם אתם...ואם לא תשמעו לי, ולא תעשו את כל המצות האלה....
If you walk in My statutes and keep my commandments and do them.....but if you do not hearken unto Me and will not to all these commandments.... (Leviticus 26:3, 14)
Much of Leviticus 26 details what happens if you obey or disobey G-d's commandments (also known as תוכחה). If you behave properly, G-d will provide such rewards as rain for your crops (Leviticus 26:4). However, if you mess up, it means that many curses will befall you, including terror and disease (Leviticus 26:16), dried-up land (Leviticus 26:20), and being smote (Leviticus 26:17). If we take the פשת (pshat; literal/plain meaning) the way we would have to interpret the passage is that our behavior has a direct causal effect on what happens to you (Rashi's commentary on Leviticus 26:3). "Do a mitzvah and you will be rewarded. Perform a transgression and G-d will give you your comeuppance." Too bad it doesn't fall that neatly into place, and here is where I take issue with a simplistic reading on the passage.
First, what is implicit in the passage is an all-or-nothing mentality. What happens when you make a mistake? It's human to err, so is G-d taunting us with an impossible task? Whatever happened to all the elements of forgiveness that exist within Judaism? Second, all of these rewards and punishments take place in the physical world, in the present world (העולם הזה). Since there is no explicit mentioning of an afterlife in the Torah [or the Tanach], does this mean that G-d is delivering all of His divine retribution in the here and now? It would explain why the concept of an afterlife in Jewish eschatology is post-Biblical in nature. Third, I believe in a G-d that is flawless. If He were going to deliver divine retribution, I would expect the correlation between performing mitzvahs and receiving reward to be unambiguous (i.e., R-squared value is equal to 1). There are evil individuals who enjoy material wealth and there are plenty of good individuals out there who suffer, which makes theodicy a legitimate concern here. In a cold, dark, cruel world that has plenty of injustice, how can we even begin to accept a literal or simplistic reading of this passage? Is there something else we can glean from this before becoming dismissive?
Nachmanides points out that G-d is not addressing individuals, but rather a community, which is why it's interesting to interpret it through a public policy lens. What happens when a community or a society enacts a top-notch policy? The populace and its quality of life are better off. When a detrimental policy becomes a part of society, the effects are adverse, and the community suffers as a result. It sounds alluring, but this is not a political treatise; it's a theological text, and we should interpret the verse within that context. Conversely, it's also possible to say that the results of society's actions can still be extrapolated from the text. Regardless, I don't find it to be the most compelling of interpretations.
R. Ibn ben Ezra has a different take on the matter, which is that because we are physical beings, we don't have an understanding of the spiritual world. G-d is essentially putting the punishment in terms that we can understand. Personally, I think G-d could have done a better job at conveying a sense of the spiritual world in the Torah instead of sidestepping it. While I think ben Ezra's interpretation has some truth in it, I think it's better to modify the interpretation in classifying the passage as a form of hyperbole to make a point. But this begs the question of what good would hyperbole do?
I believe that this hyperbolic passage is to get us to conduct some contemplative reflection on two levels. First is that our actions have repercussions. What we do as human beings is significant. One person can make a difference, and we shouldn't forget that society is still made up of individuals. The ideas that humans can come up with can create or destroy societies. Our words can uplift or knock down others. Our actions affect others, and can do good or harm. We should take the time to do some spiritual bookkeeping and work on improving ourselves.
The second goes back to that tease of "if we can't act perfectly, why bother" that I mentioned earlier. Much like with singing Dayenu during Passover, we're not meant to blindly accept what's put in front of us. It's meant to be a springboard for conversation. Maybe we're supposed to realize that we are only human and that tying our material circumstances to how we perform in life is tenuous. Perhaps we take a cue from Rambam (Hilchot Teshuva 9) and realize that true reward and punishment is not in terms of material possessions and wealth, but in something more transcendent, whether that is enjoying life's experiences [with others] or fostering a sense of spirituality in life. By realizing that "money doesn't buy us happiness," we can find a meaningful, more spiritually enriching life.