Бамидбар (Числа) 28:18

כל מלאכת עבדה [YE SHALL DO] NO SERVILE WORK — even work that is a necessity for you, as, for instance, a matter that may become lost (that cannot be postponed without irretrievable loss) and which is permissible on the intermediate days of Passover and Tabernacles (lit., the week days of the Festival) is forbidden on the Festival itself (see Rashi on Leviticus 23:8).

בַּיּ֥וֹם הָרִאשׁ֖וֹן מִקְרָא־קֹ֑דֶשׁ כׇּל־מְלֶ֥אכֶת עֲבֹדָ֖ה לֹ֥א תַעֲשֽׂוּ׃

On the first day shall be a holy gathering; you shall do no manner of servile work on it.