The intervening days between Rosh Hashana and Yom Kippur, while not formally part of either holiday, bear considerable resemblance to 'Chol HaMoed', the mid-holiday periods of Passover ('Pesach') and Tabernacles ('Sukkot'). These are days on which, while work is not totally prohibited, are also far from ordinary. Moreover, they maintain and magnify the spirit of the season, here one of acute awareness of the Absolute Sovereignty of God, the urgency of repentance and expectation of a merciful judgement.
This is accomplished in a variety of ways, via period-long liturgical emendations, interpolations and additions, as well as by other single symbolic acts. The Aramaic language 'Kaddish' (Sanctification of God's Name) is a key, repeatedly recited, feature of communal worship services, serving to separate distinct prayer sections. During these days, one word of it is doubled (L'eylah U'leylah) while combining two others (Min Kol to Mikol), so as to preserve total word count, thus proclaiming God as (exceedingly) beyond any blessing. Similarly, when taking out the Torah on the intervening Shabbos Shuvah (Sabbath of Return), "(and Awesome) is His Name" is added.
During the Amidah (Silent Standing prayer), at the conclusion of the third introductory blessing, 'Kedushas HaShem'( Holiness of God's Name), God is addressed as the 'Holy King', rather than as the usual, 'Holy God'. The same change is made in the Friday evening prayer, 'Shield of our Forefathers'. On weekdays, in concluding the eleventh blessing, 'Restoration of Justice', the year-round appellation of 'the King Who loves righteousness and judgement' is replaced by 'the King of Judgement'.
Throughout this period, four petitionary phrases are interpolated into the first two and the last two blessings of the Amidah. During the first blessing, 'Avos' (Patriarchs), "Remember us for life, O King, Who desires life, and inscribe us in the Book of Life - for Your sake, O Living God" is recited. The insertion in the second blessing, 'Gevuros' (God's Might), is "Who is like You, Merciful Father, Who recalls His creatures, mercifully for life". At the penultimate blessing, 'Modim' (Thanksgiving), "And inscribe all the children of Your covenant for a good life" is expressed. The last blessing, 'Shalom' (Peace), now concludes "In the book of life, blessing, and peace, good livelihood, may we be remembered and inscribed before You - we and Your entire people the Family of Israel for a good life and for peace".
It will be observed that, while there is provision for the insertion of private petitions in one's silent devotion, such as for recovery from illness, all Jewish prayer is collective, always 'we', not 'I' This comports well with Hillel's great dictum, "Do not separate yourself from the congregation" (Avoth 2:5). Worshippers should be concerned for the welfare of fellow congregants and for the Jewish people as a whole. Moreover, when praying alone, one's personal faults come to the forefront. Within a congregational setting, one shares in its strengths.
Following the weekday Reader's Repetition of the Amidah, the Ark containing the Torah scrolls is opened and 'Avinu Malkenu' (Our Father, our King) recited. Otherwise reserved for fast days, it is a series of now forty-four petitions, grown from an original five, first intoduced by Rabbi Akiva in a time of deepening drought. These range from pleas for forgiveness from sin, through protection from enemies, natural disasters and plague, to provision of sustenance. Five are slightly altered as reflective of the period: "Our Father, our King, inscribe us in the Books of: good life, redemption and salvation, sustenance and support, merits, forgiveness and pardon. Giving them especial emphasis, these are intoned by the Reader and repeated by the congregation. The petitions conclude with "Our Father, our King, be gracious with us and answer us, though we have no worthy deeds; treat us with charity and kindness and save us"
In many congregations, Psalm 130 ("Out of the depths I called You"), also known in Latin as 'De Profundis', is daily recited, line by line, by Reader and congregation, just prior to the morning service's central section. On weekdays over this period, prior the morning service, there is also recitation of Selichot (Penitential Prayers). Based around the Thirteen Attributes of Mercy (Ex. 34:6-7), these centuries old piyuttim (poems) for mercy, whose recitation began in late Elul, share fixed common features but vary considerably in length from day to day, with those on Rosh Hashana eve particularly lengthy and those on the day before Yom Kippur, particularly concise. On the intervening Shabbos Shuvah, a special composite haftarah is read of selections (Hosea 14:2-10, Joel 2:11-27 and Micah 7:18-20) from Twelve Prophets, emphasizing the season's themes of repentance and forgiveness.
The day after Rosh Hashana is commemorated with the daylight hours Fast of Gedaliah, which marks the assassination by zealots of Gedaliah, the Babylonian-appointed viceroy(Kings II 25:25). Thus ended the brief period of self-rule after the Babylonian conquest and destruction of the First Temple.
One-time symbolic acts over these days include, 'Hatoras Nedarim' (Renunciation of Vows), 'Tashlich' (Casting off of sins), and 'Kaporos' (Atonement Exchange).
Jews take vows very seriously. The Torah explicitly demands "Whatsoever comes out of his mouth, he shall do" (Num. 30:3). This is held to encompass much more than the there referenced vows of personal abstention. Over the course of the year, statements concerning projected actions can often be casually made and quite quickly forgotten or proven difficult, if not next to impossible, of fulfillment. Consequently , religious Jews, often add the words, "B'li Neder" (no vow intended) to such statements. Nonetheless, it's quite easy to slip up. Thus the need for a mechanism to erase retroactively such unintended oversights so as to free oneself from such sins before the Days of Judgement. It is a Bes Din, an impromtu court of any three knowledgeable individuals.
Preferentially on Rosh Hashana eve, but on any weekday throughout this period, a petitioner stands before them and recites a formulaic statement, indicating regrets for any promises, whether forgotten and thus unkept, or remembered but regretted. The judges hearing that plea respond thrice formulaicly, annulling such casual committments. "Just as does the earthly court, so may do the Heavenly Court". Responding anew, the petitioner assures the Bes Din "regarding them all, I regret them from this time and forever".
It will be noted that Hataras Nedarim forms the model for Yom Kippur's starting 'Kol Nidre' (All vows) declaration. It was originally introduced into the evening service by congregations in the Iberian Peninsula, welcoming into their midst those Spanish and Portuguese Jews forcibly converted to Catholicism, but secretly clinging to their innermost former faith. In our day, perhaps, it more broadly welcomes those estranged or largely unengaged who, if only by a thread, still seek spiritual sustenance in their ancestral faith.
Tashlich is a much beloved practice, dating back to medieval times. People, whether singly or in groups, go to a nearby body of water, preferably one with live fish. That particular aspect emphasizes the inherent uncertainties of life. Humanity perpetually is poised. as Ecclesiastes 9:12 poses: "as the fishes that are taken in the net". Preferentially, the rite is performed on the first afternoon of Rosh Hashana (the second, if the first falls on the sabbath), but can be done throughout this period, even as late as Hoshana Rabbah (the day of water judgement).
Tashlich derives from the prophet Micah (7:18-20): "Who, O God, is like You, Who pardons iniquity and overlooks transgressions for the remnant of His heritage? Who has not retained His wrath eternally for He desires kindness; He will again be merciful to us. He will suppress our iniquities and cast into the depths of the sea all their sins. Grant truth to Jacob, kindness to Abraham, as You swore to our forefathers from ancient times".
These verses, as well as Ps 118:5-9 ("From the straits did I call unto God ; He answered me with expansiveness") are recited. Kabbalists have parsed these two sets of verses as mirroring two fervent pleas of Moses (Ex. 34:6-7 and Num. 14:18), uttered respectively after the sin of the Golden Calf and that generation's rejection of the Land. Typically also recited, are Psalms 33 (which mentions "waters of the sea") and 130 ("From the Depths").
A controversial Yom Kippur eve ritual, 'Kapparot', now practiced largely by Chassidim in its original form, historically involved live chickens. Going back to at least the 9th Century, it seems reflective of a central element of the Temple Yom Kippur service: symbolic transference of sins to a scapegoat.(Lev. 16:20-22). A live chicken, or more commonly now, paper currency, is swung over one's head while reciting, for males or females, whether individuals or groups, an appropriate variation of the following: "This is my exchange, this is my substitute, this is my atonement. This chicken will go to its death [this money will go to charity] while I will enter and go to a good, long life, and to peace."
Thc chicken is then ritually slaughtered and donated to the poor for their pre-holiday meal. The currency is similarly donated. It is those charitable acts that alone give meaning to this symbolic ritual. "But charity deliveth from death" (Prov. 10:2).
On Yom Kipput eve, the Afternoon Mincha prayer is recited early so as to give congregants ample time to return home for a large pre-holiday meal. An unusual feature of its individual Silent Standing prayer is the recitation of the extended Yom Kippur Confessional, lest some mishap or illness prevent one from being able to recite it on Yom Kippur itself. It is also customary for many men to go to the 'mikveh' (ritual bath) in the afternoon, so as to enter the rapidly advancing Day of Awe in ritual purity.