仁王經疏 3.61

3.61

Explanation: Second, the direct explanation of the Dharma of protection. There are eight lines of verse expounding four principles, which are divided into four parts: the first two verses expound the principle of impermanence; the second two verses expound the principle of suffering; the third two verses expound the principle of emptiness; and the fourth two verses expound the principle of non-self. This is the first.
Within this there are three parts: first, one verse determines the impermanence of the destruction of the receptacle world during the eon; next, half a verse explains the impermanence of one lifetime of the inner body; and finally, half a verse compares the superior to highlight the inferior.
As for "When the burning of the eon reaches its end": when the fire disaster first arises, it begins from the wind wheel and extends up to the First Dhyāna; hence it is said to "reach its end."
As for "Heaven and earth are thoroughly ablaze": qian is heaven, and qian means vigorous; the movements of heaven never cease, hence it is called qian. Kun is earth, and kun means compliant; the earth accords with the four seasons, giving birth to and nurturing the myriad things, hence it is called kun. Heaven and earth are both burned through, hence it is called "thoroughly ablaze."
As for "Mount Sumeru and the vast oceans": mountain and waters are paired together, both becoming ashes and cinders.
Next, there is half a verse: devas and nāgas wither and die, all due to karma. According to the Sūtra of the Wise and the Foolish, devas, nāgas, humans, and ghosts perish within it.
As for "When the two primal forces must perish, what reliance is there on a kingdom?": this compares the superior to highlight the inferior. Just as stated above, the receptacle world and sentient beings—the two primal forces of heaven and earth—must suffer destruction and demise; how much more so will a kingdom not be annihilated!