By Rabbi Reuven Taragin
רַבִּי יַעֲקֹב אוֹמֵר, הָעוֹלָם הַזֶּה דּוֹמֶה לִפְרוֹזְדוֹר בִּפְנֵי הָעוֹלָם הַבָּא. הַתְקֵן עַצְמְךָ בַפְּרוֹזְדוֹר, כְּדֵי שֶׁתִּכָּנֵס לַטְּרַקְלִין:
הוּא הָיָה אוֹמֵר, יָפָה שָׁעָה אַחַת בִּתְשׁוּבָה וּמַעֲשִׂים טוֹבִים בָּעוֹלָם הַזֶּה, מִכָּל חַיֵּי הַעוֹלָם הַבָּא.
וְיָפָה שָׁעָה אַחַת שֶׁל קוֹרַת רוּחַ בָּעוֹלָם הַבָּא, מִכָּל חַיֵּי הָעוֹלָם הַזֶּה
At the end of Avot’s fourth perek, Rebbi Yaakov makes two statements about the relationship between this world and the next (Olam HaBa). The two statements connect with one another and together define the focus and goal of life in this world.
A Mere Corridor
Rebbi Yaakov begins by comparing this world to a corridor that leads to a palace—the next world (Avot 4:16). This comparison has two implications: The first is that this world is not the end goal. There is a bigger, better, nicer, and more meaningful place—the “palace”—we reach after passing through this world, which is a mere corridor. We are, of course, familiar with this world, drawn to its pleasures, and focused on its reality and challenges. Rebbi Yaakov teaches that this world is, in essence, just the “promo”—just the hallway.
The Mesillat Yesharim opens by explaining (based on our Mishnah) that we need to realize that we were not created (mainly) for this world (Mesillat Yesharim 1). Our souls ultimately seek things more meaningful than what this world has to offer, and we should ensure not to get lured astray by the non-spiritual aspects of our world.
This concept connects to two other statements of Rebbi Yaakov. The first is his assertion that Hashem rewards mitzvah observance only in the next world, not in this one (Kiddushin 39a). Understandably, reward is given in the palace, not the corridor.
Rebbi Yaakov also expresses this idea in the second Mishnah above, where he teaches that: “One hour of tranquility in the World to Come is more precious than all of life in this world” (Avot 4:17). As opposed to this world, in which one can never be completely happy, the next world offers us true peace, satisfaction, and tranquility. Reward is given only in the next world because one moment of peace and tranquility there is greater than a whole life of pleasure here. Knowing and appreciating this should help us avoid pursuing the pleasures of this world. Doing so would be selling ourselves short. 
The Way In
All this does not mean that there is no importance to this world or that there is no significance to the hallway. Though not the ultimate end, life in the hallway is very important, and our time here needs to be maximized.  We see this from the first part of the (second) Mishnah where Rebbi Yaakov asserts that “One hour of repentance and good deeds in this world are more precious than all of the World to Come” (Ibid). Though the next world is the world of reward and satisfaction, we earn that reward and satisfaction through our actions and personal reflection in this world. Though only a corridor, it is where we prepare to enter and earn our place in the palace.
Rebbi Yaakov emphasizes the need to take advantage of life in this world as well when he urges, “Prepare yourself in the corridor, so that you may enter the palace” (Avot 4:16). The right to enter the Olam HaBa palace is earned through our efforts in olam ha’zeh. 
Kohelet Rabbah (4:5) adds (to Rebbi Yaakov’s statement) that: “The next world is earned only by what we do in this world.” Like passing through a corridor that is the sole entry to the palace, preparation in this world is the only way to gain entry to the next one. Our efforts in this world are not just one way forward; they are the sole opportunity to earn and enhance our portion in the next world.
The Gra expressed this idea with his last words, spoken while crying on his deathbed. His talmidim asked him why he was crying. Was he afraid of facing his Maker? What did he think he would be punished for? The Gra responded that he was crying over the fact that he would soon be unable to perform mitzvot and earn reward. The Gra appreciated the unique opportunity life in this world offers. Only here can we perform mitzvot and enhance our eternal life in the palace of the world to come.
There are two additional important lessons to be learned from Rebbi Yaakov’s words. We learn the first lesson from his usage of the term “sha’ah achat (one moment).” Each and every moment has significance and thus needs to be maximized and taken advantage of. Rebbe Yehuda HaNasi famously quipped, “Some acquire their share in the next world through one moment (as opposed to others who need many years)” (Avoda Zara 10b). Each moment can and should be of great significance and impact. 
Action And Reflection
A second lesson is about the primary importance of deed and self-reflection. Instead of Torah and chochmah, Rebbi Yaakov focuses on teshuvah (repentance) and ma’asim tovim (good deeds) as the meaningful content of our world. Though Torah study is obviously a central focus of our time and energy, its significance is in how it drives us to build our identity and live our lives properly.  As the Gemara in Kiddushin states, “Study is great(er), for study leads to action.” 
Today And Tomorrow
I think we can summarize Rebbi Yaakov’s teachings using the Gemara in Eruvin which explains the Torah’s emphasis (Devarim 6:6 and many other places) on the need to do mitzvot today with five words: “Ha’yom la’asotam, machar l’kabel scharam” (Eruvin 22a)—Today (this world) is when we work. Tomorrow (the next world) is when we receive reward.
May we maximize every day of this world by realizing that we are here to reflect and grow.
Prepared for print by Yedidyah Rosenwasser.
Rabbi Reuven Taragin is the dean of overseas students at Yeshivat HaKotel.
1] See Chovot HaLevavot (Avodat Elokim Perek 9) who compares life in this world to one given access to riches for only a year. If he is wise, the person will seek to move the riches to the place he will be after the year.
2] The Radvaz (She’eilot u’Teshuvot Radvaz, 3:555) talks about someone who didn’t cry when he lost a relative because he said “he was now in a better place.” He mentioned to him that this isn’t the Jewish approach, and that this is the approach of philosophers who see no value in this world. Judaism sees every moment in this world as valuable and as a way to prepare for the next world, so we definitely do and should cry over a person who can no longer work to prepare and improve himself.
3] Rav Saadya Gaon (Emunot V’Deiot Maamar 10) emphasizes this point.
4] The Gemara in Kiddushin (49a) teaches that if a man is mekadesh a woman on the condition that he is a tzaddik, we need to consider the possibility that they are married even if we know the man to be a rasha because he may have had teshuvah on his mind. Even a moment of mere intention can change a person’s nature and identity
5] See Ramban (Shichichat Asa’ein 15) who explains that the mitzvah (mi’d’Orayta) to recite birkot haTorah is (only) because of the fact that the Torah includes guidance a list of the actions that help us earn a place in the next world.
6] Kiddushin 40b. See also Sfat Emet (Emor 5643) who learns from our Mishnah that a life lived with commitment to Hashem is greater than a moment of willingness to give up one’s life for our values.