First Blessing 3: Rashba: Blessings
“Blessed are You, Hashem.”
“You are the source of all blessing,” — Rashba, Rabbi Samuel ben Aderet, 14th century. This is the explanation that is the most universally accepted.
And this too, is the idea of a blessing. All should bless God and thank Him saying that He is the One Who blesses and all blessings come from Him.
According to the Rashba, when saying the words, Baruch Ata Hashem, one must have in mind that “You, God, are the source of all blessing. You are Baruch. You are blessing.”