וַיְהִ֣י בַשָּׁנָ֣ה הַ֠חֲמִשִׁית לִיהוֹיָקִ֨ים בֶּן־יֹאשִׁיָּ֤הוּ מֶֽלֶךְ־יְהוּדָה֙ בַּחֹ֣דֶשׁ הַתְּשִׁעִ֔י קָרְא֨וּ צ֜וֹם לִפְנֵ֧י יְהוָ֛ה כָּל־הָעָ֖ם בִּירֽוּשָׁלִָ֑ם וְכָל־הָעָ֗ם הַבָּאִ֛ים מֵעָרֵ֥י יְהוּדָ֖ה בִּירוּשָׁלִָֽם׃
Now it came to pass in the fifth year of Jehoiakim the son of Josiah, king of Judah, in the ninth month, that they proclaimed a fast before the LORD, all the people in Jerusalem, and all the people that came from the cities of Judah unto Jerusalem.
Read halakhic rulings (Jewish law) on Jeremiah 36:9 from the Mishneh Torah and classical halakhic sources, free online.