Who knows 70? In honor of Rabbi Gila Ruskin

יְמֵֽי־שְׁנוֹתֵ֨ינוּ בָהֶ֥ם שִׁבְעִ֪ים שָׁנָ֡ה וְאִ֤ם בִּגְבוּרֹ֨ת ׀ שְׁמ֘וֹנִ֤ים שָׁנָ֗ה וְ֭רׇהְבָּם עָמָ֣ל וָאָ֑וֶן כִּי־גָ֥ז חִ֝֗ישׁ וַנָּעֻֽפָה׃

Psalms 90:10

The span of our life is seventy years,
or, given the strength, eighty years;
but the best of them^-b are trouble and sorrow.
They pass by speedily, and we are in darkness.^-c

In the biblical world, the number 70 is “typological”; that is, it is used for rhetorical effect to evoke the idea of totality, of comprehensiveness on a large scale, is opposed to the use of seven on a smaller scale. Thus, according to Genesis 46:27, the entire household of Jacob that went down to Egypt comprised 70 souls. The representative body of the entire community of Israel in the wilderness consisted of 70 elders, as recorded in Exodus 24:9 and Numbers 11:24; and the prophet Ezekiel, in 8:11, uses the same figure at the end of the period of the monarchy. ....

Baal Haturim asks why the ע in the word Shema is bigger. He explains that the גמטריא of the letter ע is 70, and the 70 represents the 70 names for Israel, 70 names for the Torah, 70 ways to explain the Torah, and that Hashem seperated us from the 70 nations of the world. ("שמע") (Devarim ו:ד)

תהילים ע׳:ה׳

יָ֘שִׂ֤ישׂוּ וְיִשְׂמְח֨וּ ׀ בְּךָ֗ כׇּֽל־מְבַ֫קְשֶׁ֥יךָ וְיֹאמְר֣וּ תָ֭מִיד יִגְדַּ֣ל אֱלֹקִ֑ים אֹ֝הֲבֵ֗י יְשׁוּעָתֶֽךָ׃

Psalms 70:5

But let all who seek You be glad and rejoice in You;
let those who are eager for Your deliverance always say,
“Extolled be God!”

תהילים ע״א:ט׳

אַֽל־תַּ֭שְׁלִיכֵנִי לְעֵ֣ת זִקְנָ֑ה כִּכְל֥וֹת כֹּ֝חִ֗י אַֽל־תַּעַזְבֵֽנִי׃

Psalms 71:9

Do not cast me off in old age;
when my strength fails, do not forsake me!

רש"י על תהילים ע״א:ט׳:א׳

לעת זקנה. אם זקנתי בחטאים כלומר שחטאתי הרבה:

Rashi on Psalms 71:9:1

at the time of old age If I have aged with sins, meaning, I have sinned exceedingly.

בעל שם טוב, נח ס״ז:א׳

מהבעל שם טוב ביאור ענין אל תשליכני לעת זקנה, הכוונה שאל ישליך העת לידי זקנה, כי לפעמים נופל העבודה של האדם לידי זקנה באמצעות המשך הזמן וכו':
(אור המאיר פ' יתרו)

Ba'al Shem Tov, Noach 67:1

The Baal Shem Tov explained the verse (Psalms 71:9) "Do not cast me away in the time (le'et) of my old age." This means that you should not cast away the moment (et) and let it grow old. For sometimes it happens that your worship grows old as time goes by.

Rabbeinu Bahya, Bereshit 11:4:8

...Furthermore, they had calculated the precise number of steps needed to ascend to heaven (70) [according to Pirke de Rabbi Eliezer, the number reflects 70 miles, a mile per step. Ed.] The number may also allude to the 70 representatives of the 70 nations in the celestial spheres. ...

רד"ק על בראשית ב׳:י״ז:ב׳

מות תמות, תהיה נגזרת עליך מיתה יותר קרוב ממה שהיה ראוי לך, ודרשו רז"ל (ב"ר י"ט) כי פירש ביום יומו של הקב"ה והוא אלף שנים ואדם חי אלף שנים פחות שבעים והניח לזרעו לדורות הבאים אחריו שנאמר ימי שנותינו בהם שבעים שנה (תהלים צ' י'); ...

Radak on Genesis 2:17:2

מות תמות, mortality will be decreed for you as something occurring far sooner than would have been the case otherwise. Our sages (Bereshit Rabbah 19,8) explain that the word ביום does not refer to a day of our lives, i.e. a period of 24 hours, but refers to a “day” in G’d’s calendar, i.e. 1000 years in terms of our lives. Man was henceforth not to reach the age of 1000 years. Adam, who had been slated to live for 1000 years, actually lived only 930 years, having bequeathed the other 70 years to his descendants. They base this on Psalms 90,10 ימי שנותנו בהם שבעים שנה, “the number of years of our lives is 70.” ...

Kiddush: Holding the Divine Presence in Our Hands
by Joel Hecker
Elsewhere, the Zohar indicates that there are 70 words in kiddush, signifying the 70 crowns with which we adorn Shechinah. In rabbinic literature, the number 70 connotes completion or universality. Thus, decorating Shechinah with 70 words suggests that we have the capacity to make Her replete with all dimensions of holiness, making Her supreme.
This kabbalistic description — densely layering natural, liturgical, biblical and human images — invites us to participate in taking responsibility for how divinity is manifest in the world. As we initiate the Sabbath day, the onus is placed on us to model for our families and friends the qualities of Shechinah, a holy mixture of lovingkindness and rigor, and to remind those gathered around our Shabbat table that we have the power to invoke divinity in this world.
When you hold the kiddush cup in your hands, take a moment to contemplate that you are cradling Shechinah Herself, bringing divine aspects of love and discipline to your performance of the ritual. Kabbalists will often take one further step, holding the cup in one’s right hand, symbolizing compassion, and lightly supporting the right hand with the left, as yet another demonstration of how we want our Shabbat to be filled with love, yet accompanied by consistency and commitment, as represented by the left hand.
For the kabbalists, these symbolic associations are not mere ideas. Rather they are portals to a transformed reality, in our hearts and in the world. Bringing a transformed consciousness to the ritual brings us into intimate connection with these different aspects of God — and as a result, with those aspects in each other.