Every Jewish blessing begins with “Baruch Ata Hashem…”, Blessed are You Lord…who commanded us… Why do Jewish blessings begin this way? (Items in parens are explanations added by me.)
The main purpose of (Jewish) prayer is to arouse a fervent desire and passion to have G-dliness that is above the worlds revealed below in this world. This is the meaning of the word “Baruch” (blessing). Baruch means Hamshacha which means drawing down. We thus request from Hashem in every blessing “Please draw Your revelation down into this world. We desire to see You and be with You.”
By each blessing we request to draw down G-dly revelation and Oar Ein Sof (the Connection or Power or Light of the Infinite) into that matter of the blessing. Such as in the blessing of Rofei Cholim (healing the sick) we request from Hashem to draw the revelation into this physical world in a way that it is expressed by breaking nature and healing the sick. In the blessings of Birchas Hashanim we request that the G-dliness become revealed and cause rain to come down and vegetation to grow.
This ability is only found in prayer, in contrast to Torah (learning the holy words of G-d) and Mitzvos (performing the commandments of G-d), as only prayer has the ability to change the nature of the world through revelation, however a Mitzvah does not change the physical nature. For example when one dons Tefillin no physical change is seen to occur to the leather of the Tefillin. Thus in conclusion we see that each one of the 18 blessings in Shemoneh Esrei (the standing silent prayer that is central to Jewish prayer services) serves as a conduit to hold the revelation of Oar Ein Sof in this world.
Excerpted from Likkutei Torah – by the First Rebbe of Chabad Lubavtich, Parshas Balak. English translation via Shulchanaruchharav.com.