The passage is an excerpt from an 1823 essay on Macbeth by Thomas De Quincey:
From my boyish days I had always felt a great perplexity on one point in Macbeth. It was this: the knocking at the gate, which succeeds to the murder of Duncan, produced to my feelings an effect for which I never could account. The effect was, that it reflected back upon the murderer a peculiar awfulness and a depth of solemnity; yet, however obstinately I endeavoured with my understanding to comprehend this, for many years I never could see why it should produce such an effect.
I know "reflect on" means "To consider or think back on something," but I think this meaning doesn't fit here in the above passage.
Can we equate "reflect back upon" with "produce in"? I mean, "it [the knocking] produced in the murderer a peculiar sense of awfulness..."? Does it have anything to do with the writer feeling sympathy for the murderer?