The Menorah and the Harp

The menorah in the Beit Hamikdash only had seven candles. Seven is associated with the natural order of things. Eight is higher than nature. The Chanukah menorah’s eight candles to hint to this higher level of light.

A similar concept applies to the kinor, the harp was played in the Beit Hamikdash.

The harp used in the Beit Hamikdash had seven strings. The future Beit HaMidash will be built by Moshiach and will be everlasting. The harp used in the future Beit Hamikdash will reflect this higher level. Therefore, it will have eight strings.

(Maimor Mitzvos Ner Chanukah 5714)