Sefer Tiferes Shmuel asks why it is necessary to say that he blessed them “on that day.” He answers by quoting the verse (1 Malachim 2-3) that says that Dovid told his son Shlomo, “I am going in the way of all of the land.” The Alshich Hakadosh explains that he was telling his son to constantly remember that the way of the world is that everyone will eventually pass away. Therefore, one must properly use every second of life.
The pasuk in Tehillim (39:6) states: “Behold, You made my days as tefachim (handbreadths).” Rav Simcha Bunim of Peshischa zy”a explains that a person’s life can be measured in tefachim. To illustrate, this can be compared to a person who is using a long tape measure to measure a room. The tape may be very long, but all he has in his hands at the moment is an inch or two. So too, all a person has in his hands at any given moment is that specific moment, which is what he must focus on.
This is the meaning of the words of Rav Eliezer (Avos 2:10): “Repent one day before you die.” A person should view each day as if it is his only day, and each individual day should be divided into moments. When one views life like that, his davening and learning will be on a very high level. He will daven with kavanah and learn with zeal, for he views each moment as indispensable.
In this vein, Chazal say (Brachos 5A) that one’s yeitzer tov should always be on the offensive against his yeitzer hara. If he wins, that is fine and good. If he does not, he should engage in Torah study. If that doesn’t work, he should say Kriyas Shema. If even that doesn’t work, he should remember the day of death.
The Meforshim ask why remembering the day of death is not the first step to defeat the yeitzer hara. They explain that in order to learn, daven and say Kriyas Shema properly, one must, in fact, think about the day of death, and realize that he will have to give as reckoning of all of his actions. Thus, that is part of everything that one must do to fight the yeitzer hara. This was Dovid’s intent when he said that he was going the way of all of the land. He meant that every second of his life, he kept in mind that he would die one day, and this helped him serve Hashem on the highest level.
We can now explain that when the pasuk says that Yaakov blessed his grandsons on “this day”, the intent is that he gave the bracha of “this day”, meaning that they should always focus on each day individually as if it were there only day on earth. In this way, they would be able to overcome the yeitzer hara and serve Hashem fully and completely.
