Webtheologian and philosopher dr. Peter kreeft gives a nice summary of these different choirs and their roles in his book angels and demons: The first three levels see. Webin the sacred liturgy, christ our lord performs the work of our redemption through sacramental signs. The liturgy then is a solemn experience, and therefore sacred music. Church musicians need to be thoroughly familiar with sacrosanctum concilium, the general instruction on the roman missal, musicam sacram, john paul ii's chirograph. Webthe fall contributed to disturbing the original harmony whose memory lives in us and which we must rediscover: “the canticle of praise is rooted in the church. Webthe latin text speaks of the multitude of the choirs of angels, joining with the voices of the many saints (cum angelis, et archangelis, cum thronis, et.