In this week's parsha Hashem floods the whole world (except the land of Israel--Zevachim, 113b).
The Mishna (Pirkei Avos, 5;2) states: "There were ten generations from Adam to Noach, to show how great was His patience, for every one of those generations provoked Him continually until he brought upon them the waters of the Flood."
The Torah (6;13) tells us that Hashem flooded the world due to stealing. The commentators explain that the people stole at amounts less than a "perutah" (comparable to a penny) so that they could not be taken to court. Interestingly, Rashi (6;11) tells us that the people were also guilty of sexual immorality and idolatry...
The obvious question arises: Why did Hashem punish them due to stealing "pennies" when they were also engaging in sexual immorality and idolatry? Surely those 2 sins are far more severe!?!
Additionally, if for 10 generations Hashem was constantly provoked, why did he destroy the world due to such a seemingly petty sin?
To answer these 2 questions, I think we need to examine the 3 sins...
Idolatry (serving other g-ds) is something in which people do in order to become closer to the master of the world. Although serving idols is a sin, it is mostly done with positive intentions (to become closer to G-d) and comes about through lack of knowledge of the real master of the world (Hashem). Therefore, perhaps for this reason the sin of idolatry wasn't great enough to cause Hashem to flood the world. Now, sexual immorality is a sin in which people perform due to uncontrollable desires, mainly due to the Yetzer Hara. At this point in history Hashem hadn't given over the torah and its laws. Therefore, perahps due to the strong pull of the Yetzer Hara and the unawareness of its prohibition, the sin of sexual immorality wasn't great enough to cause Hashem to flood the world.
However, why was stealing objects worth less than a "perutah" a great enough sin to flood the world?
Stealing is something in which doesn't need to be told that it's prohibited, for it is obviously wrong to take something which is not yours! A person doesn't need a law to figure out that he shouldn't steal from others...Therefore, perhaps it was for this reason that Hashem destroyed the world due to stealing, albeit it was less than a perutah at a time...
I think we could say there's a lot more to it...Stealing shows there's a problem with a person's middos (character traits), for one should respect his fellow's property.
Why should lack of middos cause Hashem to flood the world? What's the greatness of good middos?
The Midrash (Vayikra Rabbah, 13;3) says that as a whole, the mitzvot were given to enable us to refine our character. Rabbi Chaim Vital (A.K.A. The Arizal) says that the torah doesn't obligate us to have good middos because they're the very essence of the whole torah. He explains that if one possesses good middos then he'll come to fulfill all the mitzvot with ease. Similarly, Rabbeinu Yona (Pirkei Avos, 3;21) states that the torah will not rest upon one with bad middos. Furthermore, the Gemara (Eruvin, 100b) states that had we not been given the torah then we would have been obligated to learn good middos from nature. For example, we would have had to learn modesty from cats, theft from ants, forbidden relations from doves and how to have relations from roosters. Lastly, the Midrash (Vayikra Rabbah 9:3) states that derech eretz (proper behavior) precedes the torah.
We could now understand why Hashem flooded the world due to people stealing "pennies" from each other...The torah was given in order to perform the mitzvot, and the mitzvot were given in order to improve our middos. Therefore, middos are in effect the foundation of the entire torah. Thus, for stealing from one another and thereby not showing good middos, Hashem flooded the world.
Summary: After 10 generations of constantly being provoked, Hashem decided to flood the world due to the generation of Noach stealing from each other at amounts less than a "perutah" (comparable to a penny) among idolatry, sexual immorality and many other sins because it shows bad middos (character traits). The Midrash (Vayikra Rabbah, 13;3) tells us that the mitzvot, for which the torah was created, were given to us in order so that we should refine our middos. In fact, the Arizal explains that the torah doesn't obligate one to have good middos because they're the foundation of the whole torah! Therefore, we should all learn from the generation of Noach to correct all our character flaws, for the consequences could be deadly!