These, i.e. others of the Levites; of whose several offices he had spoken before. Are the singers; or rather, were, which is understood, and all along in the foregoing and following verses, and again in this very verse. In the chambers; where they waited, that they might be ready to come whensoever they were called to the service of God in the tabernacle. Were free from all trouble and employment, that they might wholly attend upon the proper work. Employed in that work; either composing or ordering sacred songs; or actually singing; or teaching others to sing them. Day and night, i.e. continually, and particularly in the morning and evening, the two times appointed for solemn service and offerings.
Related Commentaries of 1 Chronicles 9:33
1 Chronicles 9:33
33 And these are the singers, chief of the fathers of the Levites, who remaining in the chambers were free: for they were employed in that work day and night.