Changing different material body is described here: mṛtyu-saṁsāra-vartmani (BG 9.3). Mṛtyu. Because with any body, material body, either cat's body, a dog's body or human being's body or demigod's body or even Brahmā's body, you have to die. There is no escape. Therefore it is called mṛtyu-saṁsāra-vartmani. And the, another path is, that . . . Aprāpya mām. This mṛtyu-saṁsāra-vartmani means you don't get Kṛṣṇa. Kṛṣṇa says aprāpya, "not getting mām, Me." Two alternatives. Either you get Kṛṣṇa and go back to home, back to Godhead, this is one path. And the other path that you remain in this material world and repeatedly get a body and die again, get again another body. This is going on: repetition of birth, death, old age and disease.
So Kṛṣṇa is, because He is our supreme father, supreme friend . . . Suhṛdaṁ sarva-bhūtānām. Kṛṣṇa says,
- bhoktāraṁ yajña-tapasāṁ
- sarva-loka-maheśvaram
- suhṛdaṁ sarva-bhūtānāṁ
- jñātvā māṁ śāntim ṛcchati
- (BG 5.29)
For our happiness we require cooperation of some friend. That is our practical experience. But if we make Kṛṣṇa as our supreme friend . . . He is supreme friend. He's so supreme friend that . . . You'll find in the Bhagavad-gītā, everything is explained. Īśvaraḥ sarva-bhūtānāṁ hṛd-deśe 'rjuna tiṣṭhati (BG 18.61). Sarva-bhūtānām. Of all living entities, within the core of the heart Kṛṣṇa is sitting there, along with the living entity. The living entity is also within the heart, and the supreme living entity, Kṛṣṇa, is also sitting by him.