The Botchatcher Rav shares an insightful answer that he heard from the tzadik Reb Moshe Leib of Sasov. He says that the words "בַּיּדֹם 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 "בַּיּדֹם הַהוּא לֵאמֹר," because he intended to continue with an additional blessing; the blessing of remaining focused on the present day.
(מחזה אברהם ויחי ד"ה גם ויברכם)
The Tiferes Shmuel of Alexander adds insight, saying that this instruction of בַּיּדֹם 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.
How to Be a Strong Man
Similarly, we find this concept in Alshich Hakadosh, where he draws upon the last words of Dovid Hamelech to his son Shlomo. In his parting message, Dovid Hamelech gave a line of instructions to his son Shlomo. וַיִּקְרְבוּ יְמֵי־דָוִד לָמוּת וַיְצַו אֶת־שְׂלֹמֹה בְנוֹ לֵאמֹר אָנֹכִי הֹלֵךְ בְּדֶרֶךְ כָּל־הָאָרֶץ וְחָזַקְתָּ וְהָיִיתָ לְאִישׂ And Dovid's days were nearing the time when he would die, and he commanded his son, Shlomo, saying: "I am going in the way of all the (inhabitants of) earth; be strong and be a man" (מלכים א' ב' א-ב).
The Alshich Hakadosh says that these words should be understood as an instruction, rather than an introduction to his parting words. Dovid commanded his son to constantly say to himself: "I am soon going the way all the inhabitants of the earth do".
With this, Dovid Hamelech wanted his son to regularly remind himself that our days on earth are numbered. Therefore he should always envision himself as though he will have no more days to live. By referring to this day as his last day, he will "be strong and show himself as a man", that is, serve Hashem with utmost perfection. When living with such a mindset, he will surely strive to serve his Creator to the best of his abilities.
A Handbreadth of Life
The same idea is expressed by the Rebbe, Reb Bunim of Peshischa on the possuk "הִנֵּה טְפָחוּת נָתַתָּה יָמַי," You have made my life just handbreadths long (תהלים לט ו). He says that this possuk imparts a profound lesson on how we ought to perceive life. Our lives here on earth are analogous to a long rope. Even when holding a long rope, one has only one hand's breadth in their grasp at a time, while the rest of the rope's length lies either before or after their hand. Similarly, we should not view life as a long, endless stretch, but rather focus on the fleeting moment at hand and endeavour to make the most of it. We must realise that we cannot control the past or the future, so we should not worry about them or, for that matter, depend on them. Just like the length of the rope, they are not in our "hands".
This possuk encourages us to live in the present and appreciate each instant, no matter how small or seemingly insignificant it seems. It reminds us that every moment in life is precious, and we should make the most of every opportunity that comes our way.
(תפארת שמואל ויחי אות ו)
One Day at a Time
The result of this approach is twofold. On the one hand, it provides us with a certain peacefulness, clearing the way for better Avodas Hashem. On the other hand, viewing life with this perspective will lead us to a constant sense of urgency to perfect our deeds and thoughts and to a life of repentance and closeness to Hashem. Chazal say, "אֵין 'וְעַתָּה' אֶלָּא תְּשׂוּבָה," the use (in the Torah) of the phrase "and now" indicates an opportunity for repentance. (בראשית רבה כא ו)
By living in the present moment, one becomes more mindful of their actions and is able to reflect on their deeds immediately. This introspection helps us ensure that we are fulfilling our duties to the best way possible. Therefore, the phrase "and now" serves as an indication of teshuvah, which is achieved through constant focus on the present.
In the Mishnah, Rabbi Eliezer teaches us that, "וְשׂוּב יוֹם אֶחָד לִפְנֵי מִיתָתָךְ," repent one day before your death (אבות פ"ב י). The Gemara relates (שבת קנג ע"א) that Rabbi Eliezer's students were perplexed by his teaching, since no one can predict the exact day of their death. Rabbi Eliezer clarified that this uncertainty is precisely what he meant. He suggested that if we consider every day as if it were our last day, we will be more likely to utilise it and take greater responsibility over our actions. This, in turn, will ensure that we are in a constant state of repentance throughout our entire life.