Negative commandment · Lo Ta’aseh #326 of 613
Not to work on the first day of the seventh month [the day of Rosh HaShanah]
שלא לעשות מלאכה באחד לחודש השביעי
The verse · Vayikra 23:25
כׇּל־מְלֶאכֶת עֲבֹדָה לֹא תַעֲשׂוּ וְהִקְרַבְתֶּם אִשֶּׁה לַה׳
“You shall do no servile work: but you shall offer an offering made by fire to the Lord.”
The Rambam’s words
Not to work on the first day of the seventh month [the day of Rosh HaShanah], as [Leviticus 23:25] states concerning it: "Do not do any servile work."
שלא לעשות מלאכה באחד לחודש השביעי, שנאמר בו "כל מלאכת עבודה, לא תעשו" (ויקרא כג,כה; במדבר כט,א).
Why · Sefer HaChinuch #311
To not do work on the first day of Tishrei
“It is from the roots of the commandment of this appointed time [that it] was from the kindnesses of G-d upon His creations that He remembers them and views their deeds one day each and every year; so that the iniquities should not mount so greatly, and there be room for atonement.”
Who & when
“The prohibition of work on this day is practiced in every place and at all times by males and females.”
Where in the Mishneh Torah
Hilchot Rest on a Holiday הלכות שביתת יום טוב