Commentaire sur Chroniques 2 29:25

for by the hand of the Lord was the commandment, by the hand of His prophets that the Levites should play musical instruments. It is not written in the Torah that a sacrifice requires musical accompaniment (lit., song), but it is the commandment of the Lord, which He commanded through His prophets to accompany the sacrifice with song. Our Rabbis explained in Tractate Arachin (11a): From where do we derive that the Levites are required to play musical instruments? For it is written (Num. 4:47): “the service of the service.” Which is a service that requires another service with it? This is music with a musical instrument. “And the service of raising” may also be correctly explained in reference to song, as it is written (I Chron. 15:22): “And Chenaniah, the leader of the Levites in song (בְּמַשָּׂא) etc. because he was an expert,” for he was appointed to raise the voice of the melody of the song.