One must be extremely careful not to speak a single idle word from the recitation of the Tikun of [Shavuos] night⁴, or “Rectification,” of Shavuos night is a collection of short verses and citations drawn from the Written and Oral Torah. It is the custom of many to recite this Shavuos night. These are called the “Ornaments of the Bride,” referring to the Shechinah – the Divine Presence – which ascends to unite with G-d during the Shavuos morning prayers. until after the Kedusha prayer of Musaf.⁵ prayer, begins “A crown they will give to You – Kesser itnu Lecha…” For then, all the Ornaments of the Bride ascend.⁶, as well as the 24 possible combinations of G-d’s holy Name Ado-nai, that correspond to the Sefirah of Malchus. By reciting the Tikun of Shavuos night, one clothes the Bride – the Divine Presence – in beautiful garments that make her fit for union with the King. Thus, one should be very careful to purify his thoughts at least until this Kesser. Siddur Rav Shabsai

footnotes: ⁴ The Tikun ⁵ This prayer, recited during the Reader’s Repetition of the Musaf Amidah ⁶ There are 24 Ornaments of the Bride (See Rashi on Exodus 31:18). These correspond to the 24 books of Scripture that comprise the main part of the Shavuos night Tikun