We are beginning siman 2. A person who begins measuring his grain pile should recite a tefillah asking Hashem that there should be bracha in the pile. However, the bracha is only applicable before beginning to measure, as bracha only rests on davar hasamui min ha’ayin, something not visible. Hashem can always increase the amount of grain, but will only do so before it is measured. The purpose of measuring is in order to remove the maaser.
Maaser should be measured and not just estimated. Similarly, in Ahavas Chesed, the Chofetz Chaim understands a person should precisely measure their maaser kesafim, and not just estimate an amount.
Regarding maaser, Hashem tells u’vachanuni na bazos, we can “test” Hashem, so to say, and if we give maaser properly, Hashem guarantees va’harikosi lachem bracha ad bli dai, Hashem will repay us with abundant bracha (see Malachi 3:10). Although the simple understanding of this bracha is that a person will receive bracha in the future, Chazal understand that there will be bracha in the very pile from which the maaser was removed. However, the potential bracha is only relevant only before the pile is measured, before the increase would be noticeable.
The Chayei Adam extends this concept, and writes that any time a person is making financial calculations, such as checking their store inventory, they can recite this tefillah, as long as it is before they begin. A person cannot daven for an obvious miracle, but they can daven a bracha in whatever they are measuring.
The text of the bracha is: יהי רצון מלפניך ה’ אלהי שתשלח ברכה בכרי הזה
In the Chayei Adam’s extension, the text would be: יהי רצון מלפניך ה’ אלהי שתשלח ברכה בסחורה של חנות הזה
As long as the amount is not yet counted, one may recite this tefillah. If one is checking on something already counted (e.g., their bank balance), they cannot recite this tefillah. Even though they are not aware of the exact amount, since the balance has already been calculated by the financial institution, it is no longer considered samui min ha’ayin.
While one is counting, one recites the bracha ברוך מלך העולם השולח ברכה בכרי הזה. The Chayei Adam explains that one does not recite Hashem’s name because the guarantee for bracha is only regarding maaser. Any other measuring does not have that guarantee, so Hashem’s name cannot be recited.
Regarding the limitation that one may only recite the tefillah before they begin measuring, we see a similar concept in two other places. One whose wife is pregnant and davens for a specific gender is considered having davened a tefillas shav, a purposeless tefillah, because the baby’s gender has already been decided. Similarly, if a person is informed that a tragedy has occurred, it is a tefillas shav to daven that a specific person was spared, because the tragedy has already occured.
Regarding Leah davening that Dinah changed from a boy to a girl, The Lecehm Chamudos in his pirush to the Rosh explains that since Leah was a tzadeikes gemura, she could change nature. The average person cannot do that and therefore cannot recite such a tefillah.
Summary
- Before making any precise financial calculations, one should recite a tefillah asking Hashem to imbue the item with bracha. Reciting the tefillah after having begun is considered a tefillas shav.
- While measuring, they recite the bracha ברוך מלך העולם השולח ברכה בכרי הזה thanking Hashem to the bracha imbued in the item. One does not recite Hashem’s name.
