Question: What is the source for the verse “Baruch Shem Kevod Malchuto Le’Olam Va’ed” and what is the significance of reciting it within Keri’at Shema?
Answer: After reciting the first verse of Keri’at Shema, one should recite “Baruch Shem Kevod Malchuto Le’Olam Va’ed.” The source for this verse is the Gemara (Pesachim 56a) which states: “Rabbi Shimon ben Lakish said: The Torah states, ‘Yaakov called his children and said, ‘Gather and I shall tell you that which shall happen to you in the end of days.’ This teaches us that Yaakov Avinu wished to reveal to his children the date of the Final Redemption at which point the presence of Hashem left him.” When Yaakov saw this, he began to wonder why Hashem’s presence left him. He was concerned that perhaps one of his children was not righteous and that maybe all of his children were not destined to be the patriarchs of the Jewish nation. Just like his father fathered Esav and his grandfather fathered Yishmael, perhaps one of his children as well were not fit to father the Jewish nation. It is for this reason that Yaakov thought that he was unable to reveal the End of Days to his children.
Yaakov’s children replied, “Shema Yisrael” (i.e. listen Yisrael, which was their father’s name), “Hashem Elokeinu Hashem Echad,” just like you have only one Hashem in your heart, we too have only one Hashem in our hearts. When Yaakov Avinu heard this he replied, “Baruch Shem Kevod Malchuto Le’Olam Va’ed.”
When our Sages established the order of the daily prayer, they wanted this verse uttered by Yaakov Avinu inserted into Keri’at Shema. However, they had a dilemma: How can this verse be mentioned if Moshe Rabbeinu did not recite it (as this verse is not mentioned in the Torah)? On the other hand, if this verse is not recited, how can we not say it if ultimately, Yaakov Avinu uttered it! Thus, they established that this verse be recited in an undertone.
Our Sages teach us in the Midrash (Devarim Rabba, Parasha 2, Section 37) that when Moshe Rabbeinu ascended to the Heavens, he overheard the angels exclaiming to Hashem, “Baruch Shem Kevod Malchuto Le’Olam Va’ed.” He then brought down this verse and taught it to the Jewish nation. Since this verse is attributed to the angels, it is recited in an undertone; only on Yom Kippur, when the Jewish nation is compared to Heavenly angels, is this verse recited aloud.
When reciting this verse, one must make sure to break up the words of the verse correctly. One must be especially careful to pause between the word “Baruch” and the word “Shem”. The verse should be recited as follows (with the following pauses): “Baruch, Shem Kevod Malchuto, Le’Olam Va’ed.” Indeed, the Responsa Yachin U’Voaz (Volume 2, Chapter 42) writes, “This is how we have heard it recited by my great father and teacherzt”l. My father would chastise one who would not pause slightly between the words ‘Baruch’ and ‘Shem’. My great brother Rabbi Tzemach zt”l would bang on the Tevah (podium) in order to prevent people from connecting these two words together. Indeed, in a Siddur written by grandfather the great Rashbetz, there is a comma after the word ‘Baruch.’”
Maran Rabbeinu Ovadia Yosef zt”l would constantly remind others of this law in his classes just as the Rashbetz (Rabbeinu Shimon bar Tzemach) and his son the Rashbash (Rabbeinu Shlomo bar Shimon) have already warned us (see Responsa Yabia Omer, Volume 8, Section 11).