וַאֲהֵבְךָ, וּבֵרַכְךָ וְהִרְבֶּךָ; וּבֵרַךְ… (דְּבָרִים ז: יג)
and He will love thee, and bless thee, and multiply thee; He will also …
The Baal Haturim explains that these words are referring to zechus Avos. The Ramban explains that we should generate love by doing mitzvos with love (in order to receive a blessing with love).
It seems that in order to be blessed we need some connection to Hashem. The Baal Haturim’s approach is, HKBH will bless us because of the zechus of the Avos. The Ramban’s approach, seems to be, that in order for a brocho to be given and to be effective it must be borne out of love. Why should this be so, and where do we see this in chazal?
As per Hilchos birkas kohanim, the Kohenim are charged to give the brocho with love—b’ahava. The Magen Avraham comments that if the Kohen does not love the Jews, he should not give the brocho. Why is it so necessary to have love to give a brocho?
I heard once in the name of Rav Shlomo Zalman Auerbach a pithy idea: In general people are not very interested in receiving a brocho from the average individual. They seek only the blessings of Torah giants. Yet, when it comes to a curse, people are very concerned if they get a curse even from a relatively “small” person. Why the inconsistency?
He answers that something that is done half-heartedly does not have an effect, but something that is done whole-heartedly does. Unfortunately the “small” person who gives a curse means it whole-heartedly! Therefore, there is what to be afraid of. Whereas, the blessings from this same “small” person is usually half-hearted, and thus are ineffective.
We understand from this idea that for a brocho to be completely effective it has to be borne out of complete love. Obviously gedolei Yisrael—aside from being giants in ruchnius—have an immeasurable amount of love for each Jew, which adds to the efficacy of their brochos.
The Torah tells us that HKBH is looking for us to be loved in His eyes (by us doing mitzvahs), thus His brocho will be effective on us. This is the system with which Hashem made the world.
Yitzchak Avinu employed this idea in order to improve the efficacy of his brocho on his son. He asked him “Do something for me! Make me a meal that will bring me pleasure, heightening my love for you, and making my brocho more effective.”
At this time, where we stand between Tisha B’Av and Rosh Hashanah, trying to wipe away sinas chinam with Ahavas chinam, we can use this same method: When we acknowledge a favor done by our neighbors, let us try to say that “yasher koach” (which is a brocho) with feeling. We may be surprised to find that our blessings are indeed effective.