Text 4-8-1
The Universal Form
58.1
The  Bhagavad-gītā  gives the description of the universal form, and this description was unknown to everyone before Arjuna. Now one can have some idea of the  viśva-rūpa  after this incidence; those who are actually divine can see the universal form of the Lord. But one cannot be divine without being a pure devotee of Kṛṣṇa. The devotees, however, who are actually in the divine nature and who have divine vision, are not very much interested to see the universal form of the Lord. As described in the previous verse, Arjuna desired to see the four-handed form of Lord Kṛṣṇa as Visnu, and he was actually afraid of the universal form.
In this verse there are some significant words, just like  veda-yajñādhya-yanaiḥ , which refers to studying Vedic literature and the subject matter of sacrificial regulations.  Veda  refers to all kinds of Vedic literature, namely the four  Vedas  ( Rk ,  Yajus ,  Sāma  and  Atharva ) and the eighteen  Purāṇas  and  Upaniṣads , and  Vedānta-sūtra . One can study these at home or anywhere else. Similarly, there are  sūtras ,  Kalpa-sūtras  and  Mīmāṁsā-sūtras , for studying the method of sacrifice.  Dānaiḥ  refers to charity which is offered to a suitable party, such as those who are engaged in the transcendental loving service of the Lord, the  brāhmaṇas  and the  Vaiṣṇavas . Similarly, pious activities refer to the  agni-hotra , etc., the prescribed duties of the different castes. Pious activities and the voluntary acceptance of some bodily pains are called  tapasya . So one can perform all these, can accept bodily penances, give charity, study the  Vedas , etc., but unless he is a devotee like Arjuna, it is not possible to see that universal form. Those who are impersonalists are also imagining that they are seeing the universal form of the Lord, but from  Bhagavad-gītā  we understand that the impersonalists are not devotees. Therefore they are unable to see the universal form of the Lord.
There are many persons who create incarnations. They falsely claim an ordinary human to be an incarnation, but this is all foolishness. We should follow the principles of  Bhagavad-gītā , otherwise there is no possibility of attaining perfect spiritual knowledge. Although  Bhagavad-gītā  is considered the preliminary study of the science of God, still it is so perfect that one can distinguish what is what. The followers of a pseudo incarnation may say that they have also seen the transcendental incarnation of God, the universal form, but that is not acceptable because it is clearly stated here that unless one becomes a devotee of Kṛṣṇa, one cannot see the universal form of God. So one first of all has to become a pure devotee of Kṛṣṇa; then he can claim that he can show the universal form of what he has seen. A devotee of Kṛṣṇa cannot accept false incarnations or followers of false incarnations.