The verse cited originally continues: “I shall fill the number of your days.”וּמַמְשִׁיךְ בַּכָּתוּב "אֶת מִסְפַּר יָמֶיךָ אֲמַלֵּא",
This is the advice given to prevent feelings of self-satisfaction from arising.שֶׁזּוֹהִי הָעֵצָה הַיְּעוּצָה כְּדֵי לִפְעֹל בְּנַפְשׁוֹ הָרֶגֶשׁ שֶׁל הֶעְדֵּר שְׂבִיעוּת הָרָצוֹן.
To explain:וְהָעִנְיָן בָּזֶה
When a person contemplates that he has been given a fixed number of days,שֶׁכַּאֲשֶׁר הָאָדָם מִתְבּוֹנֵן שֶׁנִּתְּנוּ לוֹ יָמִים קְצוּבִים,
as implied by the verse:1 “Days were created,”"יָמִים יֻצָּרוּ" גוֹ',
i.e., every person has been given a fixed number of days, no more and no less,לֹא פָּחוֹת וְלֹא יוֹתֵר,
then every day, every hour, and every moment, he must carry out his Divine service to fulfill his mission in this world.וּבְכָל יוֹם, בְּכָל שָׁעָה וּבְכָל רֶגַע צָרִיךְ לַעֲבֹד עֲבוֹדָתוֹ לְמַלֵּא שְׁלִיחוּתוֹ בְּעָלְמָא דֵין,
The time when the person carries out his Divine service is also significant, because just as the material substance of the world must be elevated and refined, so too, must its time. For time is also a creation, and every moment – in the existence of the world at large and in the individual existence of a given person – was brought into being by G‑d with a specific intent and purpose.2
He is most anxious about this, so anxious that he has no opportunity at all to think about matters like his own spiritual level.הֲרֵי הוּא טָרוּד בָּזֶה כָּל כָּךְ עַד שֶׁאֵין לוֹ פְּנַאי כְּלָל לַחְשֹׁב אוֹדוֹת עִנְיָנִים שֶׁל מַדְרֵגוֹת.
Thus, he will never be absorbed in feelings of self-satisfaction because he will always be concerned with the mission he must fulfill at present.
To cite an example: Before he passed away, Rabban Yochanan ben Zakkai told his students:וְעַל דֶּרֶךְ מַאֲמַר רַבָּן יוֹחָנָן בֶּן זַכַּאי:
“I don’t know on which path I am being led.”3אֵינִי יוֹדֵעַ בְּאֵיזוֹ דֶרֶךְ מוֹלִיכִין אוֹתִי,
The incident occurred on the last day of his life. When his students entered to receive his parting blessing, they found their master crying. They asked him the reason for his tears, and Rabbi Yochanan explained that he was concerned about his fate; he did not know whether he would be led heavenward or elsewhere.
The Rebbe is focusing on the obvious question: Rabbi Yochanan was a righteous man who “was never involved in idle conversation.4 He studied for 40 years and taught for 40 years,”5 serving as the leader of the Jewish people. How is it possible that he would be in such a quandary?
Among the resolutions offered:וּמֵהַבֵּאוּרִים בָּזֶה,
Rabbi Yochanan was so preoccupied with the fulfillment of his missionשֶׁמִּצַּד גֹּדֶל טִרְדָּתוֹ בְּמִלּוּי שְׁלִיחוּתוֹ
that he did not have a chance to contemplate his own spiritual level.לֹא הָיָה לוֹ פְּנַאי לָשִׂים לֵב (צוּהֶערְן זִיךְ) לַמַּדְרֵגוֹת שֶׁלּוֹ.
He was so committed, anxious, and preoccupied with the fulfillment of his mission,וְהַיְינוּ, שֶׁהוּא טָרוּד וְשָׁקוּעַ כָּל כָּךְ (עֶר אִיז אַזוֹי פִיל פַארְיָאגְט, פַארְאֵיינְגְט אוּן פַארְטְרוּנְקֶען) בְּמִלּוּי שְׁלִיחוּתוֹ
every day, every hour and every moment,בְּכָל יוֹם וּבְכָל שָׁעָה וּבְכָל רֶגַע,
that he was not aware of what was happening with his own intellectual or emotional powers.שֶׁאֵינוֹ יוֹדֵעַ מַה נַּעֲשֶׂה עִם שִׂכְלוֹ וּמִדּוֹתָיו,
Certainly, he was not aware of the state of his hidden soul powers.וְעַל אַחַת כַּמָּה וְכַמָּה בְּנוֹגֵעַ לַמַּדְרֵגוֹת הַנֶּעֱלָמוֹת שֶׁבַּנֶּפֶשׁ.
It is explained that Rabbi Yochanan was aware that he had conducted himself righteously in thought, speech, and deed. He was, however, concerned whether or not he had refined the inner dimensions of his character. Had he elevated them or merely ignored them in his striving to carry out G‑d’s will in thought, speech, and deed?
During his life, he had not confronted this question because – as explained above – he was too preoccupied with actually carrying out his service. At this time, as his life of service was drawing to a close, his challenge was to focus on this issue.6
If the above was true of Rabban Yochanan ben Zakkai, how much more so does it apply regarding an ordinary individual! He should have no feelings of self-satisfactionוּמִזֶּה מוּבָן בְּמִכָּל שֶׁכֵּן וְקַל וָחֹמֶר שֶׁלֹּא שַׁיָּךְ אֶצְלוֹ רֶגֶשׁ שֶׁל שְׂבִיעוּת רָצוֹן,
because he knows that he must fulfill his mission every moment.כִּי, בְּיָדְעוֹ שֶׁבְּכָל רֶגַע וָרֶגַע צָרִיךְ לְמַלֵּא אֶת שְׁלִיחוּתוֹ,
If one moment passes in which he is not carrying out his tasks,וְאִם עוֹבֵר רֶגַע שֶׁאֵינוֹ עוֹבֵד עֲבוֹדָתוֹ,
then not only has he failed to use an opportunity that has been granted him to flourish in his Divine service,הֲרֵי זֶה לֹא רַק שֶׁהָיָה יָכוֹל לְהִתְעַלּוֹת וּלְשַׂגְשֵׂג בַּעֲבוֹדָתוֹ (עֶר הָאט גֶעקֶענְט שְׁטַיְיגְן) וְלֹא עָשָׂה כֵן,
but also, in this moment when he does not carry out his tasks,אֶלָּא עוֹד זֹאת, שֶׁבְּרֶגַע זֶה שֶׁאֵינוֹ עוֹבֵד עֲבוֹדָתוֹ,
he has rebelled against G‑d, King of kings,מוֹרֵד הוּא בְּמֶלֶךְ מַלְכֵי הַמְּלָכִים הַקָּדוֹשׁ בָּרוּךְ הוּא
in failing to fulfill the mission with which he has been charged.בְּכָךְ שֶׁאֵינוֹ מְמַלֵּא אֶת שְׁלִיחוּתוֹ,
As a result of contemplating this, not only will a person have no feelings of self-satisfaction –הֲרֵי, לֹא זוֹ בִּלְבַד שֶׁלֹּא שַׁיָּךְ אֶצְלוֹ הָרֶגֶשׁ שֶׁל שְׂבִיעוּת רָצוֹן,
alluded to by the term “in your land” (in the above verse) – i.e., ארצך, “your land,” shares the same root letters as רצון, “will.”בְּאַרְצֶךָ,
on the contrary, were someone to ask him, “What is happening with your ‘land’?” i.e., your will,אֶלָּא אַדְּרַבָּה, ווֶען מֶען פְרֶעגְט אִים וָואס אִיז בַּא דִיר מִיטְן בְּאַרְצֶךָ,
he will bitterly call out: “What do I care about my will? What do I care about pleasure? About love? About fear?”זוֹעֵק הוּא (שְׁרַיְיט עֶר אוֹיס) בְּמַר נַפְשׁוֹ: מַה לִּי רָצוֹן, מַה לִּי תַּעֲנוּג, מַה לִּי אַהֲבָה, מַה לִּי יִרְאָה (וָואס מִיר רָצוֹן, וָואס מִיר תַּעֲנוּג, וָואס מִיר אַהֲבָה, וָואס מִיר יִרְאָה),
How can he think about spiritual levelsכֵּיצַד יָכוֹל לַחְשֹׁב עַל עִנְיָנִים שֶׁל מַדְרֵגוֹת
when at every moment he must be on guard to ensure that, Heaven forbid, not one moment will pass in rebellion against the Kingבָּהּ בְּשָׁעָה שֶׁצָּרִיךְ לַעֲמֹד עַל הַמִּשְׁמָר שֶׁלֹּא יַעֲבֹר אֲפִלּוּ רֶגַע אֶחָד בְּמַצָּב שֶׁל מְרִידָה בַּמַּלְכוּת חַס וְשָׁלוֹם
by failing to fulfill the mission demanded of him at that particular moment!7מִצַּד הַחִסָּרוֹן בְּמִלּוּי הַשְּׁלִיחוּת בְּרֶגַע זֶה.
When a person carries out the charge: “There will not be a woman who loses her young or who is barren in your land,”וְהִנֵּה כַּאֲשֶׁר הָאָדָם מְקַיֵּם הַצִּוּוּי "לֹא תִהְיֶה מְשַׁכֵּלָה וַעֲקָרָה בְּאַרְצֶךָ",
i.e., he does everything possible to see to it that, as explained previously, his Divine service will be characterized by genuine love and fear and that it will continue and thriveשֶׁעוֹשֶׂה כָּל אֲשֶׁר בִּיכָלְתּוֹ שֶׁתִּהְיֶה עֲבוֹדָתוֹ בְּאַהֲבָה וְיִרְאָה אֲמִתִּיִּים שֶׁיֵּשׁ לָהֶם קִיּוּם,
as a result of his lack of self-satisfaction, as explained above,וּמִתּוֹךְ הֶעְדֵּר שְׂבִיעוּת רָצוֹן כוּ' כַּנִּזְכָּר לְעֵיל,
he is promised blessings from Above:8אֲזַי מוֹסִיפִים וּמַבְטִיחִים לוֹ מִלְמַעְלָה
“There will not be a woman who loses her young or who is barren in your land….”שֶׁלֹּא תִהְיֶה (בִּלְשׁוֹן הַבְטָחָה) מְשַׁכֵּלָה וַעֲקָרָה בְּאַרְצֶךָ.

Summary

Feelings of self-satisfaction can be prevented from arising by contemplating that every person has been given a fixed number of days – no more and no less – and that every day, every moment, and every hour must be used to fulfill his mission in this world. When a person contemplates this, he will be preoccupied with the fulfillment of his mission and will not have a chance to think about his own spiritual level. Thus, he will not be held back by feelings of self-satisfaction, but will continually strive to advance forward.
In this way, he will carry out the charge: “There will not be a woman who loses her young or who is barren in your land,” i.e., he will enable his love and fear to continue to thrive. As a result, he will receive truly abundant blessings from Above.