וַיְהִ֞י כְּשָׁמְעִ֣י ׀ אֶת־הַדְּבָרִ֣ים הָאֵ֗לֶּה יָשַׁ֙בְתִּי֙ וָֽאֶבְכֶּ֔ה וָאֶתְאַבְּלָ֖ה יָמִ֑ים וָֽאֱהִ֥י צָם֙ וּמִתְפַּלֵּ֔ל לִפְנֵ֖י אֱלֹהֵ֥י הַשָּׁמָֽיִם׃
And it came to pass, when I heard these words, that I sat down and wept, and mourned certain days; and I fasted and prayed before the God of heaven,
Read halakhic rulings (Jewish law) on Nehemiah 1:4: and classical halakhic sources.