Upon Yosef's arrival with his children to his father, Yaakov Avinu, Yaakov asked him to bring them closer to him so he could bless them. He blessed them that their success should be so remarkable that it should serve as an example of blessing for the whole of Yisroel. Hidden within this blessing, we find another blessing that Yaakov bestowed upon his grandchildren. One that imparts a profound lesson discernible through the Torah's nuanced expression. וַיְבָרְכֵם בַּיּוֹם הַהוּא לֵאמֹר, בְּךָ יְבָרֵךְ יִשְׂרָאֵל לֵאמֹר, יְשִׂמְךָ אֱלֹקִים כְּאֶפְרַיִם וְכִמְנַשֶּׁה He (Yaakov) blessed them on that day, to say "By you shall (the people of) Israel give blessings, saying 'May God make you like Efrayim and Menashe'".
Living the Moment
When examining these words, the phrase "on that day" raises a question: what does the Torah want to tell us by saying that Yaakov blessed them "on that day"? Even if we were not told explicitly, we would understand that it was on that day, since Yaakov Avinu passed away that same day, it couldn't have been on any other day.
The Botchatcher Rav shares an insightful answer that he heard from the tzadik Reb Moshe Leib of Sasov. He says that the words "בַּיּוֹם הַהוּא", indicate that Yaakov added a very special blessing, which incorporates an important life-lesson applicable to us all.
The blessing was that they should not carry tomorrow's worries. Instead, their thoughts will be centred on the present and its attendant needs. Rather than worrying about the next day, they will always consider themselves as if born only for this day, hence focusing solely on that day's duties.
Living with this principle, says the Botchatcher Rav, saves a person from what is referred to in the Zohar as "לִבָּא רְחִיקָא", a faraway heart. This means half-heartedly serving Hashem, without complete intention and devotion. Only when one's thoughts are removed from the past and the future can his Avodas Hashem be wholehearted. This is why he blessed them "בַּיּוֹם הַהוּא לֵאמֹר", because he intended to continue with an additional blessing; the blessing of remaining focused on the present day.
The Tiferes Shmuel of Alexander adds insight, saying that this instruction of בַּיּוֹם הַהוּא לֵאמֹר, i.e, to tell oneself that there is only the present day to focus on, serves as a prelude to the subsequent brachah. In this advice lies the keys to success in Torah and Avodas Hashem and to victory in the battle with the Yetzer Hora. He says that Yaakov was telling his grandchildren that through abiding by this principle, they will achieve great accomplishments, to the extent that they would serve as a model for all future generations to follow. בְּךָ יְבָרֵךְ יִשְׂרָאֵל, It will be this very virtue that will make them the ultimate example of blessing and success.