(יא) כָּל הַשְּׁבִיעִין חֲבִיבִין לְעוֹלָם, לְמַעְלָן הַשְּׁבִיעִי חָבִיב, שָׁמַיִם וּשְׁמֵי הַשָּׁמַיִם וְרָקִיעַ וּשְׁחָקִים, זְבוּל וּמָעוֹן וַעֲרָבוֹת, וּכְתִיב (תהלים סח, ה): סֹלוּ לָרֹכֵב בָּעֲרָבוֹת בְּיָהּ שְׁמוֹ. בָּאֲרָצוֹת, שְׁבִיעִית חֲבִיבָה: אֶרֶץ, אֲדָמָה, אַרְקָא, גַּיְא, צִיָה, נְשִׁיָּה, תֵּבֵל. וּכְתִיב (תהלים ט, ט): וְהוּא יִשְׁפֹּט תֵּבֵל בְּצֶדֶק יָדִין לְאֻמִּים בְּמֵישָׁרִים. בַּדּוֹרוֹת שְׁבִיעִי חָבִיב: אָדָם, שֵׁת, אֱנוֹשׁ, קֵינָן, מַהַלַּלְאֵל, יֶרֶד, חֲנוֹךְ. וּכְתִיב (בראשית ה, כד): וַיִּתְהַלֵּךְ חֲנוֹךְ אֶת הָאֱלֹהִים. בָּאָבוֹת שְׁבִיעִי חָבִיב: אַבְרָהָם, יִצְחָק וְיַעֲקֹב, לֵוִי, קְהָת, עַמְרָם, משֶׁה. וּכְתִיב (שמות יט, ג): וּמשֶׁה עָלָה אֶל הָאֱלֹהִים. בְּבָנִים הַשְּׁבִיעִי חָבִיב, שֶׁנֶּאֱמַר (דברי הימים א ב, טו): דָּוִיד [הוא] הַשְּׁבִעִי. בַּמְּלָכִים הַשְּׁבִיעִי חָבִיב: שָׁאוּל, אִישׁ בּשֶׁת, דָּוִד, שְׁלֹמֹה, רְחַבְעָם, אֲבִיָה, אָסָא. וּכְתִיב (דברי הימים ב יד, י): וַיִּקְרָא אָסָא אֶל ה'. בַּשָּׁנִים שְׁבִיעִי חָבִיב, שֶׁנֶּאֱמַר (שמות כג, יא): וְהַשְּׁבִיעִית תִּשְׁמְטֶנָּה וּנְטַשְׁתָּהּ. בַּשְּׁמִטִּין שְׁבִיעִי חָבִיב, שֶׁנֶּאֱמַר (ויקרא כה, י): וְקִדַּשְׁתֶּם אֵת שְׁנַת הַחֲמִשִּׁים. בַּיָּמִים שְׁבִיעִי חָבִיב, שֶׁנֶּאֱמַר (בראשית ב, ג): וַיְבָרֶךְ אֱלֹהִים אֶת יוֹם הַשְּׁבִיעִי. בֶּחֳדָשִׁים שְׁבִיעִי חָבִיב, שֶׁנֶּאֱמַר (ויקרא כג, כד): בַּחֹדֶשׁ הַשְּׁבִיעִי בְּאֶחָד לַחֹדֶשׁ.
(11) All the sevenths are always beloved. Above the seventh is beloved: Skies, skies of the skies, firmament, heavens, celestial realm, abode, and clouds. And it is written (Psalms 68:5), "extol the One who rides the clouds; the Eternal is God's name." In the lands, the seventh is beloved: Earth, ground, globe, valley, wilderness, oblivion and world. And it is written (Psalms 9:9), "And God judges the world with righteousness, judges the peoples with equity." In the generations, the seventh is beloved: Adam, Shet, Enosh, Keinan, Mahalalel, Yered and Chanoch. And it is written (Genesis 5:25), "And Chanoch walked with God." In the forefathers, the seventh is beloved: Avraham, Yitschak, Yaakov, Levi, Kehat, Amram and Moshe. And it is written (Exodus 19:3), "And Moshe ascended to God." In sons, the seventh is beloved, as it is stated (I Chronicles 2:15), "David was the seventh." In kings, the seventh is beloved: Shaul, Ish-boshet, David, Shlomo, Rechavam, Aviyah and Asa. And it is written (II Chronicles 14:10), "And Asa called out to the Eternal." In years, the seventh is beloved, as it is stated (Exodus 23.11), "But in the seventh you shall let it rest and lie fallow." In sabbatical years, the seventh is beloved, as it is stated (Leviticus 25:10), "And you shall sanctify the fiftieth year." In days, the seventh is beloved, as it is stated (Genesis 2:3), "And God blessed the seventh day." In months, the seventh is beloved, as it is stated (Leviticus 23:24), "In the seventh month on the first day."
1 Enoch 20
And these are the names of the holy angels who watch. Uriel, one of the holy angels, who is over the world and over Tartarus. Raphael, one of the holy angels, who is over the spirits of men. Raguel, one of the holy angels who takes vengeance on the world of the luminaries. Michael, one of the holy angels, to wit, he that is set over the best part of mankind and over chaos. Saraqâêl, one of the holy angels, who is set over the spirits, who sin in the spirit. Gabriel, one of the holy angels, who is over Paradise and the serpents and the Cherubim. Remiel, one of the holy angels, whom God set over those who rise.
Why Are There Seven Days in a Week? By Kristin Heineman, Colorado State University, 2020
But the week and the month are a bit trickier. The phases of the Moon do not exactly coincide with the solar calendar. The Moon cycle is 27 days and seven hours long, and there are 13 phases of the Moon in each solar year.
Some of the earliest civilizations observed the cosmos and recorded the movements of planets, the Sun and Moon. The Babylonians, who lived in modern-day Iraq, were astute observers and interpreters of the heavens, and it is largely thanks to them that our weeks are seven days long.
The reason they adopted the number seven was that they observed seven celestial bodies — the Sun, the Moon, Mercury, Venus, Mars, Jupiter and Saturn. So, that number held particular significance to them.
Other civilizations chose other numbers — like the Egyptians, whose week was 10 days long; or the Romans, whose week lasted eight.
The Babylonians divided their lunar months into seven-day weeks, with the final day of the week holding particular religious significance. The 28-day month, or a complete cycle of the Moon, is a bit too large a period of time to manage effectively, and so the Babylonians divided their months into four equal parts of seven.
Shabbat of the Full Moon by Prof. Jacob L. Wright
The seven-day weekly cycle has no inherent connection to nature. Yet it became central to Judaism, and through Judaism it now structures time and labor cycles across the globe. When the Roman emperor Constantine converted to Christianity, he adopted the seven-day week in accordance with the rotation of Shabbat (Sabbath) long established by Jews. As Christianity spread, so did the Jewish week. Although Revolutionary France, the Soviet Union, and others have occasionally tried to abolish it, the seven-day week has stood the test of time.
(ה) טוּרְנוֹסְרוּפּוּס הָרָשָׁע שָׁאַל אֶת רַבִּי עֲקִיבָא, אָמַר מַה יּוֹם מִיּוֹמַיִם, אֲמַר לֵיהּ וּמַה גְּבַר מִן גּוּבְרִין. אֲמַר מָה אֲמָרִית לָךְ, וּמָה אֲמַרְתְּ לִי. אֲמַר לֵיהּ אֲמַרְתְּ לִי מַה יּוֹם מִיּוֹמַיִם, מַאי שְׁנָא יוֹמָא דְשַׁבַּתָּא מִכָּל יוֹמָא, וַאֲמָרִית לָךְ וּמָן גֶּבֶר מִגּוּבְרִין, מַאי שְׁנָא טוּרְנוּסְרוּפּוֹס מִכָּל גּוּבְרִין. אֲמַר לֵיהּ שֶׁרָצָה הַמֶּלֶךְ לְכַבְּדֵנִי. אֲמַר לֵיהּ אַף זוֹ שֶׁרָצָה הַקָּדוֹשׁ בָּרוּךְ הוּא לְכַבְּדָהּ. אֲמַר לֵיהּ מְנָאן אַתְּ מוֹדַע לִי, אֲמַר לֵיהּ הֲרֵי נְהַר סַמְבַּטְיוֹן יוֹכִיחַ, שֶׁמּוֹשֵׁךְ אֲבָנִים כָּל יְמוֹת הַשַּׁבָּת, וּבְשַׁבָּת הוּא נָח. אֲמַר לֵיהּ לְנַגְדָא אַתְּ נָגֵיד לִי, אֶתְמְהָא. אֲמַר לֵיהּ וַהֲרֵי הַמַּעֲלֶה אֶת הַמֵּת בִּזְכוּרוֹ יוֹכִיחַ, שֶׁהוּא עוֹלֶה כָּל יְמוֹת הַשַּׁבָּת וּבְשַׁבָּת אֵינוֹ עוֹלֶה, וְהַהוּא גַּבְרָא לֶהֱוֵי בָּדַק בַּאֲבוּהִי. חַד זְמַן צָרִיךְ וּבָדַק בַּאֲבוּהוֹ, וּסְלֵק כָּל יוֹמָא דְּשַׁבַּתָּא, וּבְשַׁבַּתָּא לָא סְלֵק. בְּחַד שַׁבַּתָּא אַסְקֵיהּ, אֲמַר לֵיהּ אַבָּא מִן דְּמִיתַת אִתְעַבְדֵית יְהוּדִי, אֶתְמְהָא. מִפְּנֵי מָה עָלִיתָ כָּל יְמוֹת הַשַּׁבָּת, וְשַׁבָּת לֹא עָלִיתָ. אֲמַר לֵיהּ כָּל מִי שֶׁאֵינוֹ מְשַׁמֵּר אֶת הַשַּׁבָּת אֶצְלְכֶם בִּרְצוֹנוֹ, כָּאן הוּא מְשַׁמֵּר אוֹתוֹ בְּעַל כָּרְחוֹ. אֲמַר לֵיהּ וְכִי עָמָל יֵשׁ לָכֶם שֶׁאַתֶּם עֲמֵלִים כָּל יְמוֹת הַשַּׁבָּת, וּבְשַׁבָּת אַתֶּם נוֹחִין. אֲמַר לֵיהּ כָּל יְמוֹת הַשַּׁבָּת אָנוּ נִדּוֹנִין וּבְשַׁבָּת אָנוּ נוֹחִין...
The wicked Tinneus Rufus asked R. Akiva: 'Why does this day [the Sabbath] differ from other days?' 'Why does one man differ from other men?' he retorted. 'What did I ask you and what did you answer me?' inquired he. 'You asked m' he replied, 'why does the Sabbath differ from all other days,' and I answered you, 'Why does Rufus differ from other men' 'Because the emperor desired to honour him' said he. 'Then this day, too, the Holy One wished to honour' 'How can you prove it to me?' 'Let the river Sambatyon prove it, which carries stones the whole week but allows them to rest on the Sabbath.' 'You are evading the question!' he exclaimed. 'Then let him who brings up [the dead by] his male genital prove it' he replied, 'for every day he [the dead] comes up but not on the Sabbath' He went and made a test with his own father: every day he came up, but on the Sabbath he did not come up. After the Sabbath he brought him up [again]. ' Father' said he, ' have you become a Jew after death! Why did you ascend during the whole week but not on the Sabbath? ' 'He who does not keep the Sabbath among you of his own free will must keep it here in spite of himself'. 'But what toil have you there?' he demanded. 'The whole week we undergo judgment, but on the Sabbath we rest.'...
Prof. Jacob Wright
The Number Seven
The number seven has symbolic meanings in a wide array of ancient texts that existed long before the first biblical writings. Thus, when the Southern Mesopotamian ruler Gudea builds a temple, he dedicates it for seven days.[9] (The account may provide the rationale for an annual festival.) In the flood account from the Ninevite version of the Gilgamesh Epic, the number seven plays a special role.[10] When Enkidu dies, Gilgamesh mourns for six days and seven nights. Similarly, when the royal mother of Neo-Babylonian ruler Nabonidus dies, she is mourned for seven days and nights, parallel to seven-day periods of mourning known after the death of King Shulgi of Ur and after the Guteans invade Nippur.[11]
In epic literature from the Syrian kingdom of Ugarit, many rituals last seven days—not only mourning but also feasting.[12] In southern Anatolian and northern Mesopotamian places (such as Emar and Mari), as well as throughout southern Mesopotamia, a number of feasts, rituals, and other symbolic events are conducted for seven days. Thus, the hero Kirta, from the Ugaritic legend, undertakes a voyage as part of a military campaign that lasts seven days.[13] In Egypt too, the number seven assumed symbolic significance, likely due to foreign influence; it was often linked to creation and regeneration.[14] Even in Homeric literature, which partakes in some aspects of broader Mediterranean culture, feasts are often celebrated for seven days.[15]
Seven in the Bible
In the Bible, we can identify a broad array of activities that continue for seven days, months, or years. Many of them are ceremonial or commemorative in nature, just as we witnessed in the non-biblical evidence. They include mourning (“shiva”), feasts, weddings, temple dedications, and voyages.[16]
On the basis of this comparative evidence, we can be certain that the societies of Israel and Judah would have attached special meaning to the number seven from an early point in their histories. The question is: How did this symbolic number come to be identified with Shabbat, and when did a seven-day week become one of most basic ways of ordering time?
“Time is an illusion. Lunchtime doubly so.” ― Douglas Adams, The Hitchhiker's Guide to the Galaxy