אורח חיים קמ״דOrach Chayim 144

Se’if 1א׳

מְדַלְּגִין בַּנָּבִיא וְאֵין מְדַלְּגִין בַּתּוֹרָה מִפָּרָשָׁה זוֹ לְפָרָשָׁה אַחֶרֶת; וְהָנֵי מִילֵי בִּשְׁתֵּי עִנְיָנִים, דְּחַיְישִׁינָן שֶׁמָּא תִּתְבַּלְבֵּל דַּעַת הַשּׁוֹמְעִים, אֲבָל בְּחַד עִנְיָנָא, כְּגוֹן: אַחֲרֵי מוֹת (וַיִּקְרָא טז) וְאַךְ בְּעָשׂוֹר (וַיִּקְרָא כג, כג) שֶׁכֹּהֵן גָּדוֹל קוֹרֵא בְּיוֹם הַכִּפּוּרִים, מְדַלְּגִין, וְהוּא שֶׁלֹּא יִקְרָא עַל פֶּה, שֶׁאָסוּר לִקְרוֹת שֶׁלֹּא מִן הַכְּתָב אֲפִלּוּ תֵּבָה אַחַת; וּבַנָּבִיא מְדַלְּגִין אֲפִלּוּ בִּשְׁנֵי עִנְיָנִים, וְהוּא שֶׁלֹּא יִשְׁהֶה בַּדִּלּוּג בְּעִנְיָן שֶׁיַּעַמְדוּ הַצִּבּוּר בִּשְׁתִיקָה; וְהָנֵי מִילֵי בְּנָבִיא אֶחָד, אֲבָל מִנָּבִיא לְנָבִיא אֵין מְדַלְּגִין; וּבִתְרֵי עָשָׂר מְדַלְּגִין מִנָּבִיא לְנָבִיא, וּבִלְבַד שֶׁלֹּא יְדַלֵּג מִסוֹף הַסֵפֶר לִתְחִלָּתוֹ.

To Not Skip In the Torah From One Subject to Another; And The Laws Of The Haftarah. Containing 4 S'ifim: We skip in the Prophets, but we do not skip in the Torah from one section to another section. And this is in regards to two subjects where we are worried that perhaps the mind of the listeners will be confused, but with one subject, for example “Acharei Mot” [Lev. 16:1] and “Akh Be-asor” [Lev. 23:27] that the High Priest reads on Yom Kippur, we skip. And this is a long as one does not read by heart, as it is forbidden to recite even one word not from writing. And in the Prophets, we skip even with two subjects. And this is if one does not delay when skipping into [another] matter so that the congregation does not [have to] stand in silence [waiting]. And this is in regards to [reading] within one [book of the] Prophets, but from one [book of the Prophets] to another [book of the Prophets], we do not skip. And within the Trei Asar [i.e. Twelve Minor Prophets], we skip from prophet to prophet, as long as one does not skip from the end of the book to its beginning.

Se’if 2ב׳

נוֹהֲגִין בְּשַׁבָּת שֶׁיֵּשׁ בּוֹ חָתָן, לוֹמַר אַחַר הַפְטָרַת (הַפְטָרָה יֵשׁ אוֹמְרִים שֶׁהוּא מִלְּשׁוֹן אֵין מַפְטִירִין אַחַר הַפֶּסַח, שֶׁעִנְיָנוֹ סִלּוּק, כְּלוֹמַר סִילוּק תְּפִלַּת שַׁחֲרִית) הַשָּׁבוּעַ, שְׁנַיִם אוֹ שְׁלֹשָׁה פְּסוּקִים מֵהַפְטָרַת שׂוֹשׂ אָשִׂישׂ (יְשַׁעְיָה סא, י סג, ט), וּכְשֶׁחָל רֹאשׁ חֹדֶשׁ בְּשַׁבָּת וּבְיוֹם א', אַחַר שֶׁמַּפְטִירִין הַהַפְטָרָה בְּשַׁבָּת, אוֹמְרִים פָּסוּק רִאשׁוֹן וּפָסוּק אַחֲרוֹן מֵהַפְטָרַת וַיֹּאמֶר לוֹ יְהוֹנָתָן מָחָר חֹדֶשׁ (שְׁמוּאֵל א כ, יח מב) וְאֵין לִמְחוֹת בְּיָדָם וְע"ל סי' תכ"ה סָעִיף ב' וּבְסוֹף סי' תכ"ח הֵיאָךְ נוֹהֲגִין.

The custom on a Shabbos where a groom is present is to recite after the haftarah of (The word "haftarah": some say it is [related to] the phrase ain maftirin achar ha-pesach ["We do not eat anything after the [korban] pesach"], meaning, remove [it] [i.e. which signals the end]; that is to say, it is the removal/ending of the morning prayers) that week, two or three verses from the haftarah of "Sos Asis" ["I greatly rejoice" - Isaiah 61:10]. And when Rosh Chodesh falls out on Shabbat and Sunday, after we recite the haftarah for that Shabbat, we recite the first verse and the last verse of the haftarah of "Va-yomer Lo Yehonatan, machar chodesh" ["And Yehonatan said to him 'tomorrow will be the new moon'" - Samuel 20:18]. And one should not protest [this custom]. [And see below in siman 425, se'if 3, and the end of siman 428 for how we [Ashkenazim] practice.]

Se’if 3ג׳

אֵין גּוֹלְלִין סֵפֶר תּוֹרָה בְּצִבּוּר, מִפְּנֵי כְּבוֹד הַצִּבּוּר; וְאִם אֵין לָהֶם אֶלָּא סֵפֶר תּוֹרָה אֶחָד, וְהֵם צְרִיכִים לִקְרוֹת בִּשְׁנֵי עִנְיָנִים, גּוֹלְלִין, וְיִדָּחֶה כְּבוֹד הַצִּבּוּר.

We do not roll the Torah scroll in the presence of the congregation because of the honor the congregation. And if they only have a single Torah scroll and they have to read two topics [that are in different parts of the Torah] they may roll, and we defer the honor of the congregation.