首楞嚴義疏注經 5.4

5.4

Previously, he doubted whether cause and effect were identical or different; now, he doubts the knot and untying of faculties and dusts; hence he calls it "the second doctrinal approach." However, although the reason for the arising of faculties was broadly explained earlier, it was not explicitly pointed out where the knot lies, and the meaning of knot and untying has not yet been clarified. Hoping for an explicit demonstration that is bright and recognizable, he cited the analogy previously raised by the Buddha to illustrate his own delusion.