首楞嚴義疏注經 4.237

4.237

琴等，眾生也。妙音，藏性也。妙指，實智也。發，起用也。

The zither and so on are sentient beings. The wondrous sounds are the nature of the garbha. The wondrous fingers are real wisdom. Producing [them] is the bringing forth of function.