Prabhupāda: We are practically seeing it, that material nature . . . Some infection, this is also material nature, and if you are infected with some contaminous disease, you must suffer. They practically see it. The nature will work. Puruṣaḥ prakṛti-sthaḥ. As soon as we are in this material world . . . I am living entity, spirit soul, and because I am in this material world, I have accepted this material body under the regulation of the material laws. Otherwise why there are so many varieties of life? Here is a tree. It is standing here. We are human beings; we are also here. But when there is cold blast, scorching heat, we can go into the room, but if he has to be standing here for thousands of years . . . Why this distinction? He cannot move even an inch. It is also living entity. Why he is punished in that way? And when there will be snowfall, pinching cold, he cannot go. But a small ant, it can go from here to there. Moving and not moving, the two kinds of living entities . . . Some of them can move; some of them cannot move, sthāvara. Just like grass. We are trampling over with our legs. It cannot protest. Why these differences of grades of life? This is described here. Puruṣaḥ prakṛti-stho hi bhuṅkte (BG 13.22). What is that?
Puṣṭa Kṛṣṇa: Enjoys. Bhuṅkte prakṛti-jān guṇān.
Prabhupāda: Hmm. Because this prakṛti, nature, is made of three modes of material nature, sattva-guṇa, rajo-guṇa, tamo-guṇa. Just like we are trying to associate with sattva-guṇa—no illicit sex, no meat-eating, no gambling. So others, they are not anxious for these things. They will say, "What is the wrong there? You can do that." But because you are infecting that tamo-guṇa, you'll have to suffer.