C. F. Keil and Franz Delitzsch on 2 Chronicles 5:12

2Ch 5:12

All the Levitic singers and musicians were also engaged in it, to make the festival glorious by song and instrumental music: “and the Levites, the singers, all of them, Asaph, Heman, and Jeduthun, and their sons and brethren, clad in byssus, with cymbals, psalteries, and harps, stood eastward from the altar, and with them priests to 120, blowing trumpets.” The ל before כּלּם and the following noun is the introductory ל: “as regards.” On the form מחצררים, see on 1Ch 15:24; on these singers and musicians, their clothing, and their instruments, see on 1Ch 15:17-28 and 2Ch 25:1-8.