The Zohar, Introduction, “The Intention in the Blessing,” Item 16: …For this reason, the blessing that a person blesses the Creator awakens to bestow upon the Creator blessings from above to all the worlds.
Question: What is a blessing?
Answer: A blessing is a special force from above, the force of Bina that influences Malchut. The Creator is called Blessed if I turn to Him from Malchut with the request for the forces of bestowal to come to me, to enter me, and become part of me.
When I include these forces inside of me, it means I receive a blessing, the qualities of Bina that become included in Malchut. According to these qualities, which I received from the Creator, I can call Him Blessed. Otherwise I do not have the same qualities for which I can value and thank Him.
Why do I want to receive these qualities from Bina? It’s so that I won’t curse the Creator, but will bless Him. That is to say, all of the corrections that I try to acquire are not for my own benefit, but only in order to love, to respect, and to bless the Creator.
Therefore, the words “Blessed are You” in the blessings of prayer mean that I have already gone through the corrections enabling me to work for the sake of bestowal, that I have received blessing from Him, and am now in the quality of bestowal and love. And I bless the Creator for this opportunity.
From the 2nd part of the Daily Kabbalah Lesson 3/9/11, The Zohar