仁王經疏 3.65

3.65

Explanation: Third, two verses explain emptiness. The text is divided into two parts: first, one verse explains the emptiness of dharmas. The first line explains the imagined nature (parikalpita-svabhāva). The following three lines explain the emptiness of other-dependent nature (paratantra-svabhāva), meaning that upon the other-dependent, there is no imagined nature.
As for "Sentient beings, wriggling and squirming, all dwell as illusions": the second verse explains the emptiness of sentient beings (pudgala-nairātmya).
As for "Sound and echo are both empty; kingdoms are also like this": this makes a comparison using the superior and the inferior. It means that both sound and echo are as spoken, lacking real substantial nature; just as sound and echo are unreal and therefore empty, kingdoms are likewise so, because they are dharmas formed through causes and conditions, and are therefore also spoken of as empty.