Why Do We Count?
(א) וַיְדַבֵּר יְהוָה אֶל מֹשֶׁה בְּמִדְבַּר סִינַי בְּאֹהֶל מוֹעֵד בְּאֶחָד לַחֹדֶשׁ הַשֵּׁנִי בַּשָּׁנָה הַשֵּׁנִית לְצֵאתָם מֵאֶרֶץ מִצְרַיִם לֵאמֹר. (ב) שְׂאוּ אֶת רֹאשׁ כָּל עֲדַת בְּנֵי יִשְׂרָאֵל לְמִשְׁפְּחֹתָם לְבֵית אֲבֹתָם בְּמִסְפַּר שֵׁמוֹת כָּל זָכָר לְגֻלְגְּלֹתָם.

(1) AND THE LORD spoke unto Moses in the wilderness of Sinai, in the tent of meeting, on the first day of the second month, in the second year after the were come out of the land of Egypt, saying: (2) ’Take ye the sum of all the congregation of the children of Israel, by their families, by their fathers’houses, according to the number of names, every male, by their polls;

Rashi on Numbers 1:1

The Lord spoke... in the Sinai Desert... on the first of the month :

Because they were dear to Him, He counted them often. When they left Egypt, He counted them (Exod. 12:37); when [many] fell because [of the sin] of the golden calf, He counted them to know the number of the survivors (Exod. 32:28); when He came to cause His Divine Presence to rest among them, He counted them. On the first of Nissan, the Mishkan was erected, and on the first of Iyar, He counted them.

(לז) וַיִּסְעוּ בְנֵי יִשְׂרָאֵל מֵרַעְמְסֵס סֻכֹּתָה כְּשֵׁשׁ מֵאוֹת אֶלֶף רַגְלִי הַגְּבָרִים לְבַד מִטָּף.

(37) And the children of Israel journeyed from Rameses to Succoth, about six hundred thousand men on foot, beside children.

(יא) וַיְדַבֵּר יְהוָה אֶל מֹשֶׁה לֵּאמֹר. (יב) כִּי תִשָּׂא אֶת רֹאשׁ בְּנֵי יִשְׂרָאֵל לִפְקֻדֵיהֶם וְנָתְנוּ אִישׁ כֹּפֶר נַפְשׁוֹ לַיהוָה בִּפְקֹד אֹתָם וְלֹא יִהְיֶה בָהֶם נֶגֶף בִּפְקֹד אֹתָם. (יג) זֶה יִתְּנוּ כָּל הָעֹבֵר עַל הַפְּקֻדִים מַחֲצִית הַשֶּׁקֶל בְּשֶׁקֶל הַקֹּדֶשׁ עֶשְׂרִים גֵּרָה הַשֶּׁקֶל מַחֲצִית הַשֶּׁקֶל תְּרוּמָה לַיהוָה.

(11) And the LORD spoke unto Moses, saying: (12) ’When thou takest the sum of the children of Israel, according to their number, then shall they give every man a ransom for his soul unto the LORD, when thou numberest them; that there be no plague among them, when thou numberest them. (13) This they shall give, every one that passeth among them that are numbered, half a shekel after the shekel of the sanctuary—the shekel is twenty gerahs—half a shekel for an offering to the LORD.

(ד) וַיְשַׁמַּע שָׁאוּל אֶת הָעָם וַיִּפְקְדֵם בַּטְּלָאִים מָאתַיִם אֶלֶף רַגְלִי וַעֲשֶׂרֶת אֲלָפִים אֶת אִישׁ יְהוּדָה.

(4) And Saul summoned the people, and numbered them in Telaim, two hundred thousand footmen, and ten thousand men of Judah.

(ב) וַיֹּאמֶר דָּוִיד אֶל יוֹאָב וְאֶל שָׂרֵי הָעָם לְכוּ סִפְרוּ אֶת יִשְׂרָאֵל מִבְּאֵר שֶׁבַע וְעַד דָּן וְהָבִיאוּ אֵלַי וְאֵדְעָה אֶת מִסְפָּרָם.

(2) And David said to Joab and to the princes of the people: ‘Go, number Israel from Beersheba even to Dan; and bring me word, that I may know the sum of them.’

(א) וְהָיָה מִסְפַּר בְּנֵי יִשְׂרָאֵל כְּחוֹל הַיָּם אֲשֶׁר לֹא יִמַּד וְלֹא יִסָּפֵר וְהָיָה בִּמְקוֹם אֲשֶׁר יֵאָמֵר לָהֶם לֹא עַמִּי אַתֶּם יֵאָמֵר לָהֶם בְּנֵי אֵל חָי.

(1) Yet the number of the children of Israel shall be as the sand of the sea, which cannot be measured nor numbered; and it shall come to pass that, instead of that which was said unto them: ‘Ye are not My people’, it shall be said unto them: ‘Ye are the children of the living God.’

Talmud Bavli, Baba Metzia 42a

In something that has been weighed, nor in something that has been measured, nor in something that has been counted, only in something that is hidden from the eyes.

(כא) הוא היה אומר, בן חמש שנים למקרא, בן עשר למשנה, בן שלש עשרה למצות, בן חמש עשרה לתלמוד, בן שמונה עשרה לחפה, בן עשרים לרדוף, בן שלשים לכח, בן ארבעים לבינה, בן חמשים לעצה, בן ששים לזקנה , בן שבעים לשיבה, בן שמונים לגבורה, בן תשעים לשוח, בן מאה כאלו מת ועבר ובטל מן העולם.

(21) He [Yehudah ben Teima] used to say: Five years [is the age] for [the study of] Scripture, Ten for Mishnah, Thirteen for [observing] commandments, Fifteen for [the study of] Talmud, Eighteen for the [wedding] canopy, Twenty for pursuing [a livelihood], Thirty for [full] strength, Forty for understanding, Fifty for [giving] counsel, Sixty for mature age, Seventy for a hoary head, Eighty [is a sign of superadded] strength, Ninety for bending [stature], One hundred, is as if dead, passed away, and ceased from the world.

(כ) אלישע בן אבויה אומר, הלומד ילד למה הוא דומה, לדיו כתובה על ניר חדש.והלומד זקן למה הוא דומה, לדיו כתובה על ניר מחוק .רבי יוסי בר יהודה איש כפר הבבלי אומר, הלומד מן הקטנים למה הוא דומה, לאוכל ענבים קהות ושותה יין מגתו.והלומד מן הזקנים למה הוא דומה, לאוכל ענבים בשולות ושותה יין ישן.רבי אומר, אל תסתכל בקנקן, אלא במה שיש בו.יש קנקן חדש מלא ישן, וישן שאפלו חדש אין בו.

(20) Elisha ben Abuya says: One who learns as a child is compared to what? To ink written on new parchment. And one who learns as an elder is compared to what? To ink written on scraped parchment.

Abraham Joshua Heschel, White House Conference on Aging 1961

May I suggest that man’s potential for change and growth is much greater than we are willing to admit and that old age be regarded, not as the age of stagnation but as the age of opportunities for inner growth? The years of old age may enable us to attain the high values we fail to sense, the insights we have missed, the wisdom we have ignored. They are indeed formative years, rich in the possibilities to unlearn the follies of a lifetime, to see through the inbred deceptions, to deepen understanding and compassion, to widen the horizons of honesty, to refine a sense of fairness.