首楞嚴義疏注經 3.352

3.352

破鏡生也。前四句正破，後三句縱破。火能克金，遇必融泮，外能燒艾，內合鎔鏡。今汝不然，應非鏡出。

This refutes arising from the mirror. The first four lines are the direct refutation, and the latter three lines are the concessionary refutation. Fire can overcome metal, and upon contact, [metal] must melt; externally it can burn the mugwort, so internally it ought to melt the mirror. Since here it is not so, it surely does not come out of the mirror.