The Variant Language of Brochos
The format of the brochos is as follows: First, we mention Hashem directly in the second person, referring to Him as “You.” However, after mentioning the names of Hashem and Malchus — kingship — the language switches to the distant, third person: “Who has sanctified us with His mitzvos,” instead of “You have sanctified us with Your mitzvos.”
Hashem is both hidden and revealed. His essence is hidden — it is impossible to understand Him. Yet, He is known through His actions in the created world.
When we daven, we address the aspect of Hashem that is accessible to us, and therefore we must speak in direct, second person language. At the same time, we recognize that He is completely beyond us; the brocha changes to the distant, third person. (See the Vilna Gaon, Aderes Eliyahu, Devarim 1:6)
When the Change Occurs
At the mention of Malchus — “Melech Ha’olam” — the third person expressions begin. Several reasons are given as to why the change occurs here. Ramban (Shmos, 15:26) explains that we must give honor to the Malchus (the ruling authority), and the third person expression is more respectful. The Vilna Gaon writes that the Hebrew “Ha’olam” references “Ne’elam” — hidden; Hashem’s complete dominion is hidden from view. Since Hashem’s Malchus is hidden, we refer to it in the distant, third person form.
The Shemona Esrei is Different
The main prayer, the Amida or the Shemona Esrei, is comprised of multiple brochos, one after the other. Malchus (“Melech Ha’olam”) is not required in the adjacent brochos which follow the first one. (The Tziyoni explains that there mustn’t be the appearance of two kings sharing authority.) Since Malchus is not mentioned in these brochos, the entire long prayer is chiefly in the first person.
You might ask, where is Malchus mentioned at all in the Shemona Esrei? “Melech Ha’olam” is not mentioned, even in the first brocha!
Tosafos mentions several times that the expression “Elokei Avraham” is sufficient for Malchus: Avraham demonstrated the dominion of Hashem in the heavens and the earth.
Eliezer, the servant of Avraham, asked for Hashem’s help. Rav Yechiel Michel Feinstein noted that Eliezer’s davening corresponds to the halacha very closely. He uses the names of Hashem as we find in the brochos, and Elokei Adoni Avraham — which, according to Tosafos, corresponds to Malchus! (Chidushei Hagri”z, Bereishis 24:12)
It is also fascinating to note that initially he addresses Hashem in the direct, second person (see Bereishis 24:14) and later changes to the indirect, third person (see Bereishis 24:27).
Emuna in Tefilla
It is remarkable to see how much Eliezer trusted his davening to Hashem (see Rashi, Bereishis 24:23 and Ohr Hachayim, 24:12). He asked to be answered that very day. In fact, he was answered instantly!
Yitzchak, too, knew that the solution to his wife’s infertility would come about through prayer. Even though they were unable to bear children, he did not consider taking another wife. They would ask Hashem, who would certainly answer them.
Rashi says that Yitzchak was answered first, because of his pure lineage (tzadik ben tzadik), whereas Rivka was born into a household of wicked people (tzadik ben rasha).
Yet, it is not as simple as it seems… We know that Hashem desires the tefillos of the tzadikim, and therefore brings hardships to them, so that they should daven even more… Rav Moshe Sternbuch, in Chochma V’daas, explains that Rivka’s davening (that of the tzadik ben rasha) was more actually more precious, and therefore she was not answered immediately! Hashem desires the tefillos of the tzadikim!