Commentary for Taanit 4:3
וְאַנְשֵׁי הַמַּעֲמָד הָיוּ מִתְעַנִּין אַרְבָּעָה יָמִים בַּשָּׁבוּעַ, מִיּוֹם שֵׁנִי וְעַד יוֹם חֲמִישִׁי. וְלֹא הָיוּ מִתְעַנִּין עֶרֶב שַׁבָּת, מִפְּנֵי כְבוֹד הַשַּׁבָּת. וְלֹא בְאֶחָד בַּשַּׁבָּת, כְּדֵי שֶׁלֹּא יֵצְאוּ מִמְּנוּחָה וָעֹנֶג לִיגִיעָה וְתַעֲנִית וְיָמוּתוּ. בַּיּוֹם הָרִאשׁוֹן, בְּרֵאשִׁית, וִיְהִי רָקִיעַ. בַּשֵּׁנִי, יְהִי רָקִיעַ, וְיִקָּווּ הַמַּיִם. בַּשְּׁלִישִׁי, יִקָּווּ הַמַּיִם, וִיְהִי מְאֹרֹת. בָּרְבִיעִי, יְהִי מְאֹרֹת, וְיִשְׁרְצוּ הַמַּיִם. בַּחֲמִישִׁי, יִשְׁרְצוּ הַמַּיִם, וְתּוֹצֵא הָאָרֶץ. בַּשִּׁשִּׁי, תּוֹצֵא הָאָרֶץ, וַיְכֻלּוּ הַשָּׁמַיִם. פָּרָשָׁה גְדוֹלָה, קוֹרִין אוֹתָהּ בִּשְׁנַיִם, וְהַקְּטַנָּה בְּיָחִיד, בַּשַּׁחֲרִית וּבַמּוּסָף. וּבַמִּנְחָה נִכְנָסִין וְקוֹרִין עַל פִּיהֶן, כְּקוֹרִין אֶת שְׁמַע. עֶרֶב שַׁבָּת בַּמִּנְחָה לֹא הָיוּ נִכְנָסִין, מִפְּנֵי כְבוֹד הַשַּׁבָּת:
The standing men used to fast four times in the week; viz., from Monday until Thursday (inclusive), but they did not fast on Friday, on account of the honor due the Sabbath, nor on Sunday, that they might not (too suddenly) pass over from rest and pleasure to weariness and fasting--for that might endanger their lives. On Sunday the standing men read (the sections commencing): 'In the beginning,' etc. (Genesis 1:1-5), and, 'Let there be an expansion,' etc. (Genesis 1:6)
Bartenura on Mishnah Taanit
English Explanation of Mishnah Taanit
On Sunday [they read], “In the beginning,” and, “Let there be a firmament;”
On Monday, “Let there be a firmament,” and, “Let the waters be gathered together;”
On Tuesday, “Let the waters be gathered together,” and, “Let there be lights;”
On Wednesday, “Let there be lights,” and, “Let the waters swarm;”
On Thursday, “Let the waters swarm,” and, “Let the earth bring forth;”
On Friday, “Let the earth bring forth,” and, “And the heavens [and the earth] were completed.”
For a long section two people read and for a short section one person. [This is how they would read] at Shacharit and Mussaf.
And at minhah they assemble and read the section by heart, as they recite the Shema.
On Friday at minhah they did not assemble out of respect for Shabbat.
This mishnah mostly discusses what portions of the Torah were read during the maamad.
Section one: The men of the maamad fasted most of the week every day from Monday through Thursday. They only fasted from the morning until the night. Fasting on Friday was not considered to be respectful to Shabbat because they that would cause them enter Shabbat with a ravenous appetite. They didn’t fast on Sunday because it was considered dangerous to eat a lot on Shabbat and then fast on Sunday.
Sections two-seven: Every day of the week they would read two portions concerning the creation. This allowed them to read about all seven days within six days.
Section eight: A long section, one with more than three verses is read by two people, but a portion of only three verses is read by one person. Every day there were three aliyot to the Torah. If the first section was more than three verses, let’s say it was five verses, the first person would read the entire section and then the second person would read the third through the sixth verse. This way there would always be three aliyot and never an aliyah of less three verses.
Section nine: At minhah (the afternoon service) they would assemble but they would read by heart without using a Torah scroll.
Section ten: On Friday at minhah they wouldn’t gather together because people were getting ready for Shabbat.