Albert Barnes Commentary 2 Chronicles 7:8

"So Solomon held the feast at that time seven days, and all Israel with him, a very great assembly, from the entrance of Hamath unto the brook of Egypt." — 2 Chronicles 7:8 (ASV)

Solomon kept the feast - That is, at this same time, Solomon kept not only the Feast of the Dedication but also the Feast of Tabernacles. The former lasted seven days, from the 8th to the 15th of Tisri; the latter also lasted seven days, from the 15th to the 22nd. On the following day, the people were dismissed (2 Chronicles 7:10).