דברי הימים א, פרק ט״ו, פסוק י״ט

The bringing up of the Ark of the Covenant was a momentous occasion accompanied by a highly organized musical arrangement. The primary singers, Heman, Asaph, and Ethan, were given a very specific task. They were appointed to play copper cymbals, striking them to produce a loud, echoing sound that would resonate throughout the celebration.

Beyond the sheer volume of the music, there was a clear division of labor among the Levites [מלבי״ם]. While the designated singers played the cymbals, the gatekeepers were tasked with playing stringed instruments, such as harps and lyres. This specific arrangement presents a legal difficulty, as according to standard law, gatekeepers are strictly forbidden from assisting the singers in their musical duties.

Furthermore, the musical setup itself was highly unusual. The use of three cymbals instead of the standard one, along with an irregular number of stringed instruments, did not align with the strict rules governing the songs of the Levites in the Temple. The commentators explain these anomalies by noting the specific nature of the event. Because this was not a regular Temple service, the standard rules did not apply. Instead, it was a unique, joyous celebration orchestrated entirely for the honor of the Ark of the Covenant.