He is giving a nice example here.
- yathākāśa-sthito nityaṁ
- vāyuḥ sarvatra-go mahān
- tathā sarvāṇi bhūtāni
- mat-sthānīty upadhāraya
He says, yathā ākāśa-sthitaḥ nityaṁ vāyuḥ. The air is situated in the sky. Everyone knows it, that air is passing or blowing within the sky. And nityaṁ vāyuḥ, sarvatra-go mahān. And it is blowing everywhere. You cannot find out any place where there is no air. If you want to drive out air, then you have to make by machine, by vacuum, airtight. Otherwise, air is everywhere. Yathākāśa-sthito nityaṁ vāyuḥ sarvatra-go mahān. "As the air is spread all over, anywhere, similarly," tathā sarvāṇi bhūtāni mat-sthānīty upadhāraya, "similarly, everything that is there that is existing, it is within Me. It is within Me." Sarva-bhūtāni kaunteya prakṛtiṁ yānti māmikām. And when this manifestation, material manifestation, is dissolved, then where does it take place? Where does it go? He says, sarva-bhūtāni kaunteya prakṛtiṁ yānti māmikām: "My prakṛti, My nature, My nature, is manifested and when the time is finished, that nature is wound up." And kalpa-kṣaye punas tāni kalpa, kalpādau visṛjāmy aham: "In this way, at a certain interval, this material manifestation is exhibited, and again it is wound up."