When actually one is liberated from the bodily concept of life and he sees spiritual identity everywhere, samaḥ sarveṣu bhūteṣu, paṇḍitāḥ sama-darśinaḥ (BG 5.18), then he can be situated in the activities of Brahman. The bhakti-yoga is the activities of Brahman. The Māyāvādī philosophers, they are thinking that after Brahman realization there is no more activity. But that is not the fact. Real activity begins after Brahman realization. That is Brahman activity. That is bhakti-yoga. Kṛṣṇa is Paraṁ Brahman, and we are Kṛṣṇa's part and parcel. Naturally we are also Brahman, because part and parcel of gold must be gold. There is no doubt about it. But it does not mean that the small particle of gold is equal to the gold mine. That is not possible. Part is never equal to the whole.
So Kṛṣṇa has already described bhakti-yoga. Now He is describing about the activities of this material world. Traiguṇya-viṣayā. Activities of the material world means to act in such a way that you become liberated at the end and go back to home, back to Godhead. That is real activities of this material world, not to act as the animals—eating, sleeping, mating. So this material world is now described, compared with a banyan tree which has its root upwards, above. That means this material world is created from the spiritual world. Eko nārāyaṇa āsīt. In the spiritual world there is always Nārāyaṇa. Even Śaṅkarācārya, he says nārāyaṇaḥ avyaktāt paraḥ. The spiritual world has nothing to do with this material world. This material world is created. Just like the banyan tree. It takes its root and it is created. So the seed of the creation is in the spiritual world. Sa īkṣata, sa asṛjata. The creation is coming from the spiritual world. Spiritual world means the kingdom of God, Nārāyaṇa, or Kṛṣṇa. So here the material world is described as ūrdhva-mūlam. In other words, it is reflection of the spiritual world. Just like if you stand on the shore of a lake, you will find all the trees reflected in the water downwards. Real tree is on the shore of the lake, and the reflection is downwards. The upper part of the tree has gone down. So this material world is compared with that reflection. It is chāya. In Brahma-saṁhitā also, it is said, sṛṣṭi-sthiti-pralaya-sādhana-śaktir ekā chāyeva yasya bhuvanāni bibharti durgā (Bs. 5.44). The superintending deity of this material world is Goddess Durgā, durgā-śakti. So she creates this material world. Sṛṣṭi-sthiti-pralaya-sādhana-śaktir ekāḥ. Kṛṣṇa's energy. Kṛṣṇa also says in the Bhagavad-gītā, bhūmir āpo 'nalo vāyuḥ (BG 7.4). This material energy is His energy. The energy is always compared with feminine part. And the energetic is always compared with the male part. Male part and female part. Kṛṣṇa also said in the Bhagavad-gītā, ahaṁ bīja-pradaḥ pitā (BG 14.4). So He is the seed-giving father. Bījo 'haṁ sarva-bhūtānām (Bg 7.10). So He is the original seed of this material world. And from there, from the spiritual world, it has expanded. Ūrdhva-mūlam adhah-śākham aśvatthaṁ prāhur avyayam (BG 15.1). Avyayam, eternal. This material energy also eternal.