וְעַתָּה לֹא יִבָּצֵר מֵהֶם כֹּל אֲשֶׁר יָזְמוּ לַעֲשׂוֹת
Parashat Noach contains two main stories, the story of the Flood and the story of the Tower of Bavel. Neither of these stories depict man in a particularly positive light, with the only hero, Noah, declared righteous at the beginning of his story and passed out drunk and indecent at the end. However there is something unique about the story of the Tower of Bavel that sets it apart from not only the story of the Flood, but also the preceding stories of the first religious and moral transgressions. The Tower of Bavel is unique in that it depicts ‘א as relating to the people in an almost adversarial manner. ‘א scatters them across the land (Bereishit 11:8, 9), the exact thing they had been trying to avoid happening (11:4). The people begin each step of their construction with the phrase, “Come, let us” (11:3, 4), and ‘א turns this around on them when he decides to mix up their languages, saying, “Come, let us go down, and there confound their language” (11:7). Perhaps the strongest indicator is ‘א’s statement where He seems concerned about what the people might do next. “And the LORD said: ‘Behold, they are one people, with one language for all of them, and this is what they begin to do; And now nothing will be beyond their reach that they intend to do” (11:6). This verse is jarring not only because ‘א sounds like someone worried about what the people on the other side might do next, but also because unity and cooperation are generally thought of as causes for celebration, not destruction. By contrast, ‘א reacts to the first religious and moral sins like a disappointed parent, first giving the transgressor a chance to repent, and only then punishing them after they attempt to shirk the responsibility for their actions (3:8-19; 4:9-15), and by the generation of the Flood ‘א just seems saddened and regretful (6:6). ‘א’s adversarial tone by the Tower of Bavel stands out against the background of the preceding narratives. The reason for this tone can be found in nature of the sin of the Tower of Bavel, however, the nature of this sin is not at all clear from the text, and requires delving into the historical context of the ancient city of Bavel.
To this day if a person goes to the spot where Bavel once stood they will see the ruins of the great tower that once stood there. This tower was a place of pagan worship, dedicated to the god Marduwas, and it was renown throughout the region as the “The House of the Foundation of Heaven and Earth.” At the temple atop the tower the priests would “meet” the gods, in line with meaning of the Aramaic name for the city, “Gate of the Gods.” This was the grandest of such towers, but they were not an uncommon phenomenon in the ancient near east. Many kings had built, or restored, such towers, and often their dedications claimed that they “reached the heavens” (as 11:4) and “made a name” for the king, even earning the king a place among the gods. While building a tower for pagan worship would be problematic in its own right, the idea of a person becoming a god is a direct attack on the basic idea of monotheism, that ‘א is God, and no other.
The sin of the Tower of Bavel is a function of a group of people working together not just for the sake of Idolatry, but in order to challenge ‘א’s very nature as uniquely divine. Thus the adversarial tone in the story is not a function of ‘א setting himself against the people, but of the people setting themselves against ‘א. If then had not said, “Come, let us” build a tower against ‘א, then He would not have said, “Come, let us” destroy the tower. If they had not tried to gather together at the Tower, they would not have required scattering. And if they had not been gathered against ‘א, then their unity would not have been a reason for destruction, but a reason for celebration.
The narrative of the Tower of Bavel is a story of the crushing of ancient idolatry, but it is also more than that. The Tower of Bavel story, in its lack of clarity, challenges the reader to consider not just what the people were doing, but also why they were doing it. The fact that the people were unified is meaningless in the face of their larger intentions. Unity is not its own justification, as it can just as easily be used to build as to destroy. In the Tower of Bavel narrative, the Torah challenges us to examine not only our actions but also why we are doing them, as even the best actions can be made meaningless, or worse, by the wrong intentions. When we do anything in our daily lives, we are meant to ask, are we just doing this to make a name for ourselves, or does it serve some greater, divine, purpose?
 For an excellent discussion of some of the differing views of the Rishonim regarding the nature of the sin, as well as how they fit with the historical background of the text, see this essay by R’ Elchanan Samet, from which much of the information in the next paragraph was culled.
 It is noteworthy that the only place in Tanakh where a similar phrase occurs is in Bereishit 28:17, when Yaakov exclaims, “and this is the Gate of Heaven,” after having a vision of ‘א in a dream. This is just one of a variety of parallels between the two passages, a greater discussion of which can be found in R’ Yitzchak Etshalom’s lecture “Archaeology in Tanach.”