We have no fewer than twelve Levites standing on the platform, and we may add any number. A minor may not enter the Temple Court for the service except when the Levites are standing in song. And they would not join in the song with lyre and harp but by mouth, in order to add harmony to the melody. R’ Eliezer ben Yaakov says: They do not count in the number, and they do not stand on the platform, but they would stand on the ground, with their heads between the legs of the Levites, and they were called the Levites’ tormentors.