The Minhag to Say “Yasher Koach”
34. The minhag today is to say “yasher koach” to the Kohanim after their bracha. The reason is to show gratitude for the bracha they gave and to give them more strength and encouragement in avodas Hashem (מטה אפרים סי' תקצ''ב סי''א ). Another intent is to give the Kohanim a bracha that just as they finished this mitzva, they should be zocheh to do more mitzvos (שו''ת מהר''ם מינץ סי' פ''ה ). Even though Kohanim are commanded to bentch Klal Yisroel, one can still show them gratitude for it (ע''פ רש''ש שביעית פ''ד משנה ב').
רבונו של עולם Tefilla for a Dream
Individual in Eretz Yisroel
35. If one had a dream and does not know whether the dream was good or not good and he is in distress over it, he should stand in front of the Kohanim while they go up for Birkas Kohanim and say the רבונו של עולם tefilla for a dream (גמ' ברכות דף נ''ה ע''ב, שו''ע סי' ק''ל ).
36. Someone who did not have a dream the previous night should not say this tefilla on any given day (ביאה''ל שם ד''ה מאן ). Thus, we do not say it as a tzibbur because not everyone in the tzibbur had a dream.
In Chutz L’Aretz
37. In Chutz l’Aretz or other places where Birkas Kohanim is only done at Mussaf on Yom Tov, the minhag is for the entire tzibbur—even those who did not have a dream the previous night—to say this tefilla during Birkas Kohanim. The tefilla will be intended for all the dreams between the previous Yom Tov and the current Yom Tov (מ''ב סי' ק''ל סק''א ).
38. When it is said as a tzibbur, the minhag is for all the Kohanim to sing one tune after the shliach tzibbur calls out the final word, “שלום ,” and before they repeat it. While they sing, the tzibbur says the tefilla for a dream. Then, the Kohanim finish the word “שלום ,” and the tzibbur finishes the tefilla along with them so that they can answer Amen to both simultaneously.
39. The Kohanim should determine among themselves in advance a uniform tune to sing or whether the minhag in that place is to sing in the first place. This way, they will not end up getting mixed up and lose concentration in real time.
40. Tzibbur in Eretz Yisroel. In many communities in Eretz Yisroel where Birkas Kohanim is said daily, the minhag is not to say this tefilla as a tzibbur, because if someone had a dream, he can say the tefilla the following day; he does not need to wait until Yom Tov.
41. Nevertheless, some held on to this minhag of saying this tefilla every Yom Tov even in Eretz Yisroel, like the minhag in Chutz l’Aretz. One can include the dreams between last Yom Tov and this Yom Tov that he forgot and did not daven about the next day.
How Many Times Is the Tefilla Said?
42. Some say the tefilla “רבונו של עולם אני שלך וכו'” three times, one tefilla at the end of each of the brachos the Kohanim give, i.e., at “וישמרך ,” “ויחנך ,” and “שלום .” They finish the tefilla with the word “ותשמרני ” at “וישמרך ” at the end of the first bracha; they finish with “ותחנני ” at the end of the bracha that ends with “ויחנך ”; and they finish “ותרצני ” at “שלום ” (מ''ב סק''ד ). Some explain the three tefillos for dreams as follows: “וישמרך ” is for a dream that comes from mazikin; “ויחנך ” is for a dream that comes from the Heavenly constellations; and “שלום ” is for a dream that comes from malachim (מהרש''א ברכות דף נ''ה ).
43. Some only say this tefilla once at the end of Birkas Kohanim, when they say “שלום ,” concluding with the three words “ותשמרני ותחנני ותרצני ” (כף החיים סי' ק''ל בשם האריז''ל, שו''ע הגר''ז ).
יהי רצון Tefilla
44. There is another tefilla printed in the siddurim—“יהי רצון וכו'” (כתבי אריז''ל, ס' שערי ציון שער ג', קיצור השל''ה חולין עניני תפילת שמונה -עשרה). Some say it at the word “שלום ” at the end of Birkas Kohanim instead of the third tefilla for a dream, and they only say the tefilla for a dream twice or just once.
