2 Chronicles 7:9
And in the eighth day they made a solemn assembly: for they kept the dedication of the altar seven days, and the feast seven days.
Cross-references
2 Chronicles 30:26 explicitly compares Hezekiah's Passover joy to Solomon's temple dedication, stating no such joy since Solomon's time.
2 Chronicles 30:23 describes an extended seven-day celebration during Hezekiah's Passover — similar added festivity but not the same feast.
Leviticus 23:36 commands a solemn assembly on the eighth day of Tabernacles — the ordinance Solomon is following here.
1 Kings 8:65 is the parallel account of Solomon's fourteen-day feast (seven plus seven) before the eighth-day dismissal.
Nehemiah 8:18 records a later observance of Tabernacles with the same eighth-day solemn assembly 'according unto the manner'.
Numbers 7:10 records the dedication of the tabernacle altar — a similar event to the temple altar dedication here.
Ezra 6:16 describes the dedication of the second temple with joy, mirroring the dedication ceremony in Solomon's time.
John 7:2 refers to the Feast of Tabernacles, the same seven-day feast with an eighth day that Solomon celebrated at the dedication.