Each week as Shabbat departs and the new week begins, we recite a special havdala (differentiation) prayer. The theme of this prayer is the demarcation between the holy and the mundane, and its recitation delineates between the sanctity of Shabbat and the workweek. Our sages discuss where this prayer should be inserted in the liturgy. The Mishna offers three opinions and all three understand that havdala should be recited as part of the evening Amida prayer. The subject of disagreement is the form and placement of havdala (M. Berachot 5:2; B. Berachot 33a). The first opinion - the one adopted by normative Jewish practice - suggests that havdala should be included in the blessing regarding wisdom. The Talmud explains that we exercise our wisdom when we distinguish between different levels of holiness. Alternatively, the first three blessings of the Amida are also part of the Shabbat service, whereas the fourth blessing dealing with wisdom is the first weekday benediction and therefore should make reference to the onset of a new week. The second opinion suggests that havdala deserves to have its own additional blessing and should slot in as the fourth paragraph in the Amida, preceding all weekday blessings. The third approach holds that havdala should be recited toward the end of the Amida as part of the benedictions of thanksgiving as we thank the Almighty for the gift of Shabbat and for the ability to differentiate between the holy and the mundane. While disagreements are a staple of the Talmud, here our sages are intrigued by the havdala dispute: The Men of the Great Assembly are credited with laying the foundations of our liturgy, including the introduction of the havdala requirement. The Men of the Great Assembly was a legislative body of 120 sages and existed at the end of the Babylonian exile and the early Second Temple period. How can there be a disagreement as to where havdala should be said; where did the Men of the Great Assembly institute that it should be recited? Moreover, how did a dispute arise about a common weekly rite that was no doubt practiced for many years? The Talmud responds by recounting an interesting historical chapter that led to the dispute. Havdala was first instituted as part of the prayer service. At this time, the Jewish people were not affluent, and the Men of the Great Assembly did not seek to further burden their dire financial circumstances by requiring anything more than a paragraph of prayer. Once the Jewish people were more established, havdala was removed from the evening prayer and instead instituted over a cup of wine. Thus Shabbat was ushered in with kiddush over wine and accompanied out with havdala over wine. When the people became impoverished again, the sages sought to revert to the original requirement of havdala in prayer. While we can be proud that our sages were conscious of the financial needs of the people and sought to adapt accordingly, this continuous state of havdala flux would have entailed uncertainty. Hence the sages preferred a new arrangement: havdala should be said as part of the evening prayer and those who had the means should also recite it over a cup of wine. It was at this stage - after a period when havdala had been said only over wine and not as part of the prayer service - that the disagreement arose as to where the prayer should be recited. The Talmud offers ancient tradition that gives rise to an issue with the dual havdala arrangement: Havdala said as part of the evening prayer service is more praiseworthy than havdala subsequently recited over a cup of wine. This preference for havdala in prayer seems to make any subsequent havdala redundant. The tradition continues advocating the recitation of both forms of havdala. This leads the Talmud to ask: If havdala included in the evening prayers is preferable and appears to suffice, then isn't any subsequent havdala over a cup of wine superfluous? What is the problem with a surplus havdala blessing? The use of God's name in vain when swearing in court is a biblical prohibition (Exodus 20:7). The Talmud understands that this ban applies not just to vain oaths but also to the recitation of unnecessary blessings. The Talmud proposes that in truth the tradition was not advocating a recitation of both forms of havdala, rather it was promoting either method. The upshot of this interchange is that two havdala blessings are unwarranted and problematic. Contrary to this tradition, as we have seen, many talmudic authorities did encourage both forms, apparently not considering this a use of the holy name in vain. Indeed, further in the passage our sages do not adopt the position suggested by this tradition. Rather they rule that both havdala in prayer and over wine should be recited, as each recitation has its basis and purpose. Despite rejecting the tradition that sees a double havdala as uncalled for, the proscription against unnecessary blessings is widely accepted. Not only may a wanton use of God's name contravene a biblical prohibition, but elsewhere in the Talmud the act is understood to be in disregard of a positive commandment (B. Temura 4a). Our sages understand that uttering God's name in vain does not fulfill the positive commandment to fear the Almighty (Deuteronomy 6:13). How does the restriction on the use of the holy name affect us? We respectfully avoid calling our elders by their first names in recognition of their status. Similarly, a cautious approach to the use of God's name creates a certain distance between us and the Almighty and reflects a humble acknowledgement of God's superiority and authority. The havdala prayer differentiates between the sanctity of Shabbat and the routine weekdays. It is specifically at this time that we are reminded of the religious obligation not to use God's name in vain, for watchfully using the Almighty's name adds a dimension of holiness. It is this element of sanctity that we hope will guide us through our workweek. The writer is on the faculty of Pardes Institute of Jewish Studies and is a rabbi in Tzur Hadassah.