Or HaChaim on Exodus 25:23/אור החיים על שמות כ״ה:כ״ג

1 אמתים ארכו, its length two cubits, etc. When you "cube" the dimensions of the Table, i.e. multiplying the two cubits length by one cubit width and by one and a half cubits height, you will find that you have a total of three cubits, or three times one cubit. This corresponds to the influence on our material world by the mystical dimension of the Celestial Table which represents the three levels of נצח, הוד and יסוד.