When blessing a daughter it is traditional to say, "May G‑d make you like Sarah, Rebecca, Leah and Rachel." Why aren't Bilhah and Zilpah mentioned? I know they were "hand maidens" but they must have been special in order to give birth to four of the twelve tribes of Israel. Thank you, and may G‑d bless you and Chabad.org!
We bless our children to be like Sarah, Rebecca, Rachel and Leah because they alone are the Jewish Matriarchs. The Talmud tells us: "Only three are referred to as Patriarchs; and only four are referred to as Matriarchs." The four are a reference to Sarah, Rebecca, Rachel, and Leah.
These seven spiritual giants are considered our nation's patriarchs and matriarchs not so much because they are our shared biological antecedents, but primarily because they are our spiritual ancestors.
According to kabbalah, the souls of the Patriarchs were the embodiment of the G‑dly attributes – that transcend creation – of Kindness (Abraham), Severity (Isaac) and Harmony (Jacob); while the Matriarch's souls were the embodiment of (four components of) the Divine attribute of Royalty (Malchut).
It is from them that every Jew – their "children" – inherit these spiritual faculties. For example, our capacity to selflessly love – both G‑d and our fellow man – is an inheritance from Abraham.
Bilhah and Zilpah also had lofty souls, but not as lofty as the Matriarchs. According to the mystical teachings, their souls were also the embodiment of Royalty, as were the Matriarchs', but Royalty as it descends and invests itself in creation.
The Patriarchs and Matriarchs were utterly detached from creation, and it is from them that we receive the ability to remain unaffected by our mundane surroundings. Bilhah and Zilpah imbue every Jew with the capability to carry over the holiness we inherit from the Patriarchs and Matriarchs into creation.
This is why Bilhah and Zilpah bore these children "on behalf of" and as "the agents of" Leah and Rachel. The children they bore were even named by Leah and Rachel. Bilhah and Zilpah don't represent a unique divine attribute as do the Patriarch and Matriarchs—rather they are the conduit through which our Patriarch and Matriarchs can be manifest in our reality.
Rabbi Naftali Silberberg,
Chabad.org Editorial Team