The Megillah states: “On the seventh day, when the heart of the king was merry with wine” (1:10). The Gemara in Megillah (12b) asks why Achashveirosh’s drinking is mentioned only on day seven of the party. He most assuredly had been imbibing all along, so why does the Megillah mention it specifically at this point?
The Gemara explains that the seventh day mentioned here does not refer to the seventh day of the party but to Shabbos, the seventh day of the week. It is the day on which Klal Yisroel sit down to enjoy their seudas Shabbos, whereupon they begin to recite divrei Torah and sing zemiros to Hashem. Contrast this with how the non-Jews often spend their time, indulging in food and drink and participating in uncouth conversations.
This was, in fact, what transpired at Achashveirosh’s party. The Gemara relates that the attendees were inebriated, and they began discussing which region of the world produced the most beautiful women. Achashveirosh put an end to this discussion when he offered to demonstrate the beauty of his wife Vashti, of Chaldean descent, and commanded that she parades unclothed before all those in attendance. Her refusal to comply led to her execution, which paved the way for Esther’s entry to the palace.
Why does the Gemara’s description of Achashveirosh’s party begin with a comment about how Yidden comport themselves at their meal? The Gemara could have described Achashveirosh’s party without this seemingly irrelevant fact. Why is the fact that a Shabbos seudah includes divrei Torah and zemiros relevant to how the discussion at Achashveirosh’s party ultimately led to Vashti’s demise?