נאמרה עצירה באשה שנאמר (בראשית כ, יח) כי עצר עצר ה' בעד כל רחם ונאמרה עצירה בגשמים דכתיב (דברים יא, יז) ועצר את השמים נאמר לידה באשה ונאמר לידה בגשמים נאמר לידה באשה דכתיב (בראשית ל, כג) ותהר ותלד בן ונאמר לידה בגשמים דכתיב (ישעיהו נה, י) והולידה והצמיחה נאמר פקידה באשה ונאמר פקידה בגשמים נאמר פקידה באשה דכתיב (בראשית כא, א) וה' פקד את שרה ונאמר פקידה בגשמים דכתיב (תהלים סה, י) פקדת הארץ ותשקקה רבת תעשרנה פלג אלהים מלא מים
Reish Lakish elaborates: Closing up is stated with regard to a woman who cannot give birth, as it is stated: “For the Lord has fast close up all the wombs” (Genesis 20:18), and closing up is stated with regard to rains, as it is written: “And He will close up the heavens” (Deuteronomy 11:17).Likewise, an expression of giving birth is stated with regard to a woman, and an expression of giving birth is also stated with regard to rain. Specifically, giving birth is stated with regard to a woman, as it is written in the case of Rachel, when God had mercy on her: “And she conceived and gave birth to a son” (Genesis 30:23). And giving birth is stated with regard to rain, as it is written: “For as the rain comes down, and the snow from heaven, and does not return there, except it waters the earth and causes it to give birth and bud” (Isaiah 55:10).Lastly, an expression of remembering is stated in connection with a woman, and an expression of remembering is also stated in connection to rain. Remembering is stated in connection with a woman, as it is written: “And the Lord remembered Sarah” (Genesis 21:1), and remembering is stated in connection to rain, as it is written: “You have remembered the earth and have watered it; greatly enriching it, with the pool of God that is full of water” (Psalms 65:10).
מִי־אֵ֣ל כָּמ֗וֹךָ נֹשֵׂ֤א עָוֺן֙ וְעֹבֵ֣ר עַל־פֶּ֔שַׁע לִשְׁאֵרִ֖ית נַחֲלָת֑וֹ לֹא־הֶחֱזִ֤יק לָעַד֙ אַפּ֔וֹ כִּֽי־חָפֵ֥ץ חֶ֖סֶד הֽוּא׃ יָשׁ֣וּב יְרַֽחֲמֵ֔נוּ יִכְבֹּ֖שׁ עֲוֺֽנֹתֵ֑ינוּ וְתַשְׁלִ֛יךְ בִּמְצֻל֥וֹת יָ֖ם כָּל־חַטֹּאותָֽם׃ תִּתֵּ֤ן אֱמֶת֙ לְיַֽעֲקֹ֔ב חֶ֖סֶד לְאַבְרָהָ֑ם אֲשֶׁר־נִשְׁבַּ֥עְתָּ לַאֲבֹתֵ֖ינוּ מִ֥ימֵי קֶֽדֶם׃
Is there any divinity save You who forgives the sins and pardons the transgressions of the remnant, Your people? You do not maintain anger forever, for You delight in love.
You will return to us compassionately, overcoming the consequences of our sin, hurling our sins into the depths of the sea.
You will keep faith with Jacob, showing enduring love to Abraham, as You promised our ancestors in days of old.
Maharil Hilchos Rosh HaShanah
There was a minhag to go on Rosh HaShanah, after the meal, and throw our sins into the sea.
2. What is the reason for Tashlich?
The Maharil writes, There was minhag to go to the river and say [the pasuk of] Tashuv Terachmeinu (Michah 7:19). The reason for this is found in a midrash, (Yalkut 99) [Tashlich] is in remembrance of the time when Avrham passed through the water and it went up to his neck...But [the Sefer Minhagim] adds that we should see live fish. And it is possible that this is for an omen that the evil eye not rule over us, and that we should be fruitful and multiply as fish.
Rabbi Jonathan Saks: Commentary to Tashlikh from pp. 936-947 of Koren-Sacks Machzor for Rosh HaShana
It is a custom, on the afternoon of the first day of Rosh HaShana (or second, if the first is Shabbat) to go to the shore of the sea, the bank of a river, or other running stream of water, as a symbolic enactment of the words of the prophet Micah: "He God] will cast (tashlikh) into the depths of the sea all their sins" (Micah 7:19)...The first mention of the custom is in Sefer Maharil of Rabbi Jacob Moellin (d. 1425)...Many folk customs have become associated with Tashlikh, among them the custom of throwing crumbs into water as a symbolic gesture to accompany the process of repentance, begun on Rosh HaShana, as if we were "casting away" our sins. This practice was dismissed by some halakhic authorities and ridiculed by gentiles. However it is less ridiculous than it seems. Maimonides writers about the scapegoat on Yom Kippur over which the High priest confessed the sins of the people and which was then sent out into the wilderness:
"There is no doubt that sins cannot be carried like a burden, and taken off the shoulder of one being and laid on that of another. But these ceremonies are of a symbolic character, and serve to impress people with a certain idea, and to induce them to repent, as if to say: we have freed ourselves of our previous deeds, have cast them behind our backs and removed them frum us as far as possible (Guide III:46)."
עֲבֵרוֹת שֶׁבֵּין אָדָם לַמָּקוֹם, יוֹם הַכִּפּוּרִים מְכַפֵּר. עֲבֵרוֹת שֶׁבֵּין אָדָם לַחֲבֵרוֹ, אֵין יוֹם הַכִּפּוּרִים מְכַפֵּר, עַד שֶׁיְּרַצֶּה אֶת חֲבֵרוֹ. אֶת זוֹ דָּרַשׁ רַבִּי אֶלְעָזָר בֶּן עֲזַרְיָה, מִכֹּל חַטֹּאתֵיכֶם לִפְנֵי יְיָ תִּטְהָרוּ (ויקרא טז), עֲבֵרוֹת שֶׁבֵּין אָדָם לַמָּקוֹם, יוֹם הַכִּפּוּרִים מְכַפֵּר. עֲבֵרוֹת שֶׁבֵּין אָדָם לַחֲבֵרוֹ, אֵין יוֹם הַכִּפּוּרִים מְכַפֵּר, עַד שֶׁיְּרַצֶּה אֶת חֲבֵרוֹ. אָמַר רַבִּי עֲקִיבָא, אַשְׁרֵיכֶם יִשְׂרָאֵל, לִפְנֵי מִי אַתֶּם מִטַּהֲרִין, וּמִי מְטַהֵר אֶתְכֶם, אֲבִיכֶם שֶׁבַּשָּׁמַיִם, שֶׁנֶּאֱמַר (יחזקאל לו), וְזָרַקְתִּי עֲלֵיכֶם מַיִם טְהוֹרִים וּטְהַרְתֶּם. וְאוֹמֵר (ירמיה יז), מִקְוֵה יִשְׂרָאֵל יְיָ, מַה מִּקְוֶה מְטַהֵר אֶת הַטְּמֵאִים, אַף הַקָּדוֹשׁ בָּרוּךְ הוּא מְטַהֵר אֶת יִשְׂרָאֵל:
...Yom Kippur atones for transgressions between a person and God, but for a transgression against one's neighbor, Yom Kipur cannot atone, until he appeases his neighbor. Thus R. Eleazar ben Azariah expounds the text, "From all your sins before the Lord shall ye be clean": For transgressions between a person and God, Yom Kippur atones, for transgressions against one's neighbor, Yom Kippur cannot atone, until he appeases his neighbor. R. Akiva says, Happy are you, Israel! Before whom are you purified, and who purifies you [of your transgressions]? Your Father Who is in heaven. For it is said, "Then will I sprinkle clean water upon you, and ye shall be clean"; and it is also said, "The ritual bath [lit. Hope] of Israel is the Lord"; even as a ritual bath purifies the unclean, so does the Holy One, Blessed be He, purify Israel.