Either by further progress you have to go to the spiritual planets, otherwise you'll fall down. Just like the same example. Suppose you have got some aeroplane and you go very high in the sunshine. So what is the benefit? If you do not get shelter in the moon planet or in another planet, then you have to come back again. Similarly, sāyujya-mukti means you become one of the spiritual sparks, but, because you're part and parcel of Kṛṣṇa, you are sat-cid-ānanda. Sat, cit . . . there are . . . you have got three things within you. This mukti, sāyujya-mukti, is the sat only—eternity. You can eternally remain. But you have got other two things to fulfill: that cit and ānanda.
So, so if you want to fulfill all the pleasures of life, sat-cit-ānanda, then you have to take shelter of Kṛṣṇa. The śāstra says, āruhya kṛcchreṇa paraṁ padaṁ tataḥ patanty adhaḥ anādṛtaḥ-yuṣmad-aṅghrayaḥ (SB 10.2.32). One who has no information of Kṛṣṇa, one who does not take shelter of the lotus feet of Kṛṣṇa, he may take the sāyujya-mukti after severe penances and austerities, but again he'll fall down, because he wants ānanda. Simply impersonal, without any varieties, he cannot have ānanda. That spiritual variety is available in the Kṛṣṇaloka, in the Vaikuṇṭhaloka.
So for want of spiritual variety, you'll again like to come into the material variety. Āruhya kṛcchreṇa paraṁ padaṁ tataḥ patanty adhaḥ anādṛta-yuṣmad-aṅghrayaḥ. Ye 'nye ravindākṣa vimukta-māninas (SB 10.2.32). So this kind of mukti is not first-class mukti. Therefore Vaiṣṇavas, they do not want it. Vaiṣṇava does not want any kind of mukti. This Vaiṣṇava wants simply to remain in the service of the Lord. They don't aspire for any kind of mukti. Mama janmani janmanīśvare bhavatād bhaktir ahaitukī tvayi (CC Antya 20.29, Śikṣāṣṭaka 4). So this mukti, the sāyujya-mukti, means to become one with the Supreme, is not very safe, because there is . . . there is want of ānanda and knowledge. Simply to become one, that will not help.
Therefore he is actually, constitutionally, a small particle of sac-cid-ānanda. So for want of ānanda, he comes again. Thus we have seen many sannyāsī, they give up this world as brahma satyaṁ jagan mithyā, but they do not get any benefit out of it. Therefore they come down again to open hospitals and schools and philanthropic work. They fall down. Now, if it is brahma satyaṁ jagan mithyā, if jagat is mithyā, then why you are coming again to open hospitals? It is mithyā.
But brahma satya. If you have realized Brahman, you are truth. Then why truth is coming to untruth? Because they could not get any pleasure. They want pleasure. Simply sitting down, that "I am now Brahman, Brahman," that will not help. You must act as Brahman. You must get pleasure acting as Brahman. Then there will be ānanda. Otherwise, it is not possible. Āruhya kṛcchreṇa paraṁ padaṁ tataḥ patanty adhaḥ (SB 10.2.32). These are the śāstric injunction.