Cf. Siddur, p. 148ff.

(a) Shabbos Mevarchim:1

On a Shabbos when the new month is blessed (Shabbos Mevarchim), chassidim should assemble in shul early in the morning for the recital of the entire Book of Psalms(Tehillim). Then,for about an hour before davenen, a chassidic maamar should be studied that can be understood by all.

The time and place of the farbrengen [i.e., the chassidic gathering that is usually held, among other times, after morning prayers on Shabbos Mevarchim] should be determined by local conditions. (And may those be conditions of material and spiritual prosperity!)

After the conclusion of Tehillim on Shabbos Mevarchim, the Mourner’s Kaddish is said. If one of those present is required to say Kaddish because he is observing a yahrzeit or is a mourner, he recites Kaddish at the conclusion of each of the Five Books of Tehillim.2

On the Shabbos before Rosh HaShanah, as before any new month, the complete Book of Tehillim is read before the prayers, which are followed too by a farbrengen.

(b) A Regular Shabbos:

In the morning prayers of Shabbos and Yom-Tov one does not repeat the last verse of Psalm 91 (יושב בסתר; p. 154).3

In the Great Hallel (i.e., Psalm 136; p. 156), one should articulate the phrase כי לעולם חסדו distinctly,4 in order that the first two words should not be slurred together. Likewise, the ס of חסדו should be pronounced carefully.5

In the Great Hallel [whose verses total 26, the numerical equivalent of the Four-Letter Name of G‑d], one bears in mind the letter י [which equals ten] while reading the first ten verses, the letter ה [five] while reading the next five verses, and so forth, as indicated in the Siddur; [i.e., the letter ו (six) while reading the next six verses, and the letter ה (five) while reading the final five verses].6

In the passage following יוצר אור (p. 170) one says מה רבו מעשיל on Shabbos as on weekdays.7

In the Kedushah of Shacharis (p. 179), the word תשכון begins a new sentence.