Each morning, as part of the Pesukeh De'zimra section of the prayer service, we recite a collection of verses that begins with "Yehi Chebod Hashem Le'olam, Yismah Hashem Be'ma'asav" (Tehillim 104:31). This paragraph of "Yehi Chebod" consists of 18 verses, and the sages of Kabbalah teach that these correspond to the 18 letters in the six configurations of the Name "Sha-ddai." This Name is comprised of three letters – Shin, Dalet, and Yod – and they can be arranged in six different sequences, for a total of 18 letters. In some Siddurim, a letter appears alongside each verse to draw our attention to this correspondence. The first three verses correspond to the standard configuration of the Name "Sha-ddai," such that the first verse is associated with the letter Shin, the second with Dalet, and the third with Yod. The next three verses are connected to the sequence Shin, Yod and Dalet; the next three correspond to the sequence Dalet, Yod and Shin; the fourth set of three verses parallels the configuration of Dalet, Shin and Yod; followed by Shin, Yod and Dalet, and then Yod, Dalet and Shin. It is worthwhile to obtain a Siddur that features these letters next to each verse so one can have this intention while reciting Yehi Chebod. The Ben Ish Hai (Rav Yosef Haim of Baghdad, 1833-1909), based on the Sha'ar Ha'kavanot, writes that the Name "Havaya" appears 18 times in Yehi Chebod, alluding to the 18 "realms" of the universe identified by Kabbalistic wisdom. Many have noted, however, that this collection of verses actually includes 19 instances of "Havaya," and not merely 18. Some suggest that Yehu Chebod actually corresponds to the Amida prayer, which initially consisted of 18 blessings, but a blessing was later added to bring the total to 19. However, the Kabbalists explicitly associated the instances of "Havaya" in Yehi Chevod with the 18 "realms," and so we are left with the question of how to reconcile this tradition with the fact that "Havaya" appears 19 times in this paragraph. The answer given is that the final two verses of Yehi Chabod – "Ve'hu Rahum Yechaper Avon… Hashem Hosh'a Ha'Melech Ya'anenu…" – are not actually part of this section, and were added later. As such, the instance of "Havaya" in these final verses ("Hashem Hoshi'a") is not included in the total of mentions of this Name. This theory, however, undermines the Kabbalistic teaching mentioned earlier regarding the significance of the 18 verses in Yehi Chabod. If the final two verses are not actually part of this section, then it contains only 16 verses, and not 18. Some have answered by noting that one of the verses in Yehi Chebod – "Hashem Melech, Hashem Malach, Hashem Yimloch Le'olam Va'ed" – is not actually found anywhere in Tanach. It is a composite, made up of the beginning of three different verses – one that begins "Hashem Melech," another that begins "Hashem Malach," and a third that begins "Hashem Yimloch Le'olam Va'ed." Hence, this "verse" actually counts as three verses, bringing the total verses in Yehi Chebod to 18. Rav Yisrael Bitan, after discussing this topic, concludes that this issue gives us a glimpse into the complexity and profundity of Kabbalah, showing us how Kabbalistic teachings require in-depth study and analysis.