וַ֠יִּקְרָא בְּסֵ֨פֶר תּוֹרַ֤ת הָאֱלֹהִים֙ י֣וֹם ׀ בְּי֔וֹם מִן־הַיּוֹם֙ הָֽרִאשׁ֔וֹן עַ֖ד הַיּ֣וֹם הָאַחֲר֑וֹן וַיַּֽעֲשׂוּ־חָג֙ שִׁבְעַ֣ת יָמִ֔ים וּבַיּ֧וֹם הַשְּׁמִינִ֛י עֲצֶ֖רֶת כַּמִּשְׁפָּֽט׃ (פ)
Also day by day, from the first day unto the last day, he read in the book of the Law of God. And they kept the feast seven days;
Read kabbalistic (mystical) interpretation of Nehemiah 8:18: and classical mystical sources.