וַיְהִ֡י כִּ֣י הִקִּיפֽוּ֩ יְמֵ֨י הַמִּשְׁתֶּ֜ה וַיִּשְׁלַ֧ח אִיּ֣וֹב וַֽיְקַדְּשֵׁ֗ם וְהִשְׁכִּ֣ים בַּבֹּקֶר֮ וְהֶעֱלָ֣ה עֹלוֹת֮ מִסְפַּ֣ר כֻּלָּם֒ כִּ֚י אָמַ֣ר אִיּ֔וֹב אוּלַי֙ חָטְא֣וּ בָנַ֔י וּבֵרֲכ֥וּ אֱלֹהִ֖ים בִּלְבָבָ֑ם כָּ֛כָה יַעֲשֶׂ֥ה אִיּ֖וֹב כָּל־הַיָּמִֽים׃ (פ)
그 잔치 날이 지나면 욥이 그들을 불러다가 성결케 하되 아침에 일어나서 그들의 명수대로 번제를 드렸으니 이는 욥이 말하기를 혹시 내 아들들이 죄를 범하여 마음으로 하나님을 배반하였을까 함이라 욥의 행사가 항상 이러하였더라
Tur
Laws of Passover
It is taught: We ask and expound upon the laws of Passover thirty days before Passover. Therefore, thirty days before Passover the obligation of removal [of chametz] applies, as I will explain. I found it written: From the first of Nisan until after Isru Chag [the day after the festival], we do not fall on our faces, neither by day nor by night, and we do not say "Tzidkatecha Tzedek" at Mincha on Shabbat, and we do not fast, and we do not eulogize. As it is stated in the first chapter of Tractate Soferim: Why do we not fast in Nisan? Because on the first of Nisan the Tabernacle was erected, and the twelve princes brought their offerings over twelve days, and each one made his day like a festival. Therefore we do not fast until Nisan passes. The firstborn fast on the eve of Passover. And students fast on Monday, Thursday, and Monday because of desecration of God's name—three days. It seems to me that these three days refer to after Passover, as is customary in Ashkenaz to fast three days after Passover, and likewise after Sukkot, because these are days of feasting and rejoicing, and perhaps through this they came to sin. They based this on the verse from Job: "And it was, when the days of feasting had completed their cycle... and he offered burnt offerings according to the number of them all, for Job said: Perhaps my children have sinned."
It is taught: We ask and expound upon the laws of Passover thirty days before Passover. Therefore, thirty days before Passover the obligation of removal [of chametz] applies, as I will explain. I found it written: From the first of Nisan until after Isru Chag [the day after the festival], we do not fall on our faces, neither by day nor by night, and we do not say "Tzidkatecha Tzedek" at Mincha on Shabbat, and we do not fast, and we do not eulogize. As it is stated in the first chapter of Tractate Soferim: Why do we not fast in Nisan? Because on the first of Nisan the Tabernacle was erected, and the twelve princes brought their offerings over twelve days, and each one made his day like a festival. Therefore we do not fast until Nisan passes. The firstborn fast on the eve of Passover. And students fast on Monday, Thursday, and Monday because of desecration of God's name—three days. It seems to me that these three days refer to after Passover, as is customary in Ashkenaz to fast three days after Passover, and likewise after Sukkot, because these are days of feasting and rejoicing, and perhaps through this they came to sin. They based this on the verse from Job: "And it was, when the days of feasting had completed their cycle... and he offered burnt offerings according to the number of them all, for Job said: Perhaps my children have sinned."