בַּיּ֤וֹם הַשְּׁמִינִי֙ שִׁלַּ֣ח אֶת־הָעָ֔ם וַֽיְבָרֲכ֖וּ אֶת־הַמֶּ֑לֶךְ וַיֵּלְכ֣וּ לְאָהֳלֵיהֶ֗ם שְׂמֵחִים֙ וְט֣וֹבֵי לֵ֔ב עַ֣ל כָּל־הַטּוֹבָ֗ה אֲשֶׁ֨ר עָשָׂ֤ה יְהוָה֙ לְדָוִ֣ד עַבְדּ֔וֹ וּלְיִשְׂרָאֵ֖ל עַמּֽוֹ׃
Am achten Tage entließ er das Volk; sie segneten den König und kehrten in ihre Zelte zurück, fröhlich und guten Mutes über all das Gute, das der Herr getan seinem Knecht David und seinem Volke Israel.
Tze'enah Ure'enah
“On the eighth day he let the people go” [8:66]. Solomon sent the people home on Shemini Azeret.3Radak, I Kings, 8:66.
Tze'enah Ure'enah
Our sages do not say that they left on the festival of Shemini Azeret, but they received permission from the king on Shemini Azeret. They left after Shemini Azeret and they left joyfully and with grateful hearts for all the good that the Holy One had done for His servant David and His people Israel. It was for the building of God’s house, as Solomon had desired from God.4Radak, I Kings, 8:66.
Rashi
For Dovid His servant. To make known that He forgave them their sins, as we find in [Maseches] Mo’ed Katan.43 9a. When Shlomo wished to bring the Ark into the Holy of Holies, the gates clung to one another.
Rashi
And for Yisroel His people. That He forgave them the sin of Yom Kippur,44I.e., for having eaten on Yom Kippur. and a Bas Kol emanated and declared, “All of you are prepared for the life of the World to Come.”45Maseches Mo’ed Katan 9a.