BG Chap 11 - The superiority of the human form of Kṛṣṇa
To say that the thousand-headed form is superior to the human form of Kṛṣṇa because Arjuna needed celestial eyes to see that form is foolish talk. The personal forms of Kṛṣṇa, the two-handed form and the four-handed, are completely different from the temporary universal form shown to Arjuna. The four-handed form of Nārāyaṇa and the two-handed form of Kṛṣṇa are eternal and transcendental, whereas the universal form exhibited to Arjuna is temporary. Kṛṣṇa changes from the universal form to the four-handed form of Nārāyaṇa and then to His own natural form of two hands. This indicates that the four-handed forms and other forms mentioned in Vedic literature are all emanations of the original two-handed Kṛṣṇa. The four handed form of the Lord, Mahā-Viṣṇu, is a plenary expansion of Kṛṣṇa confirms Brahma-Saṁhitā. Bhagavad-gītā 7.7 says there is no one superior to Kṛṣṇa, and 10.2 says that He is the source of all devas.
When Kṛṣṇa changed into the thousand-headed form, Arjuna’s vision also became suitably transformed; Arjuna’s vision which could see the human form of Kṛṣṇa, the ocean of beauty and charm was not suitable to see the thousand-headed form. Thus, it should be understood that Arjuna’s eyes were endowed with powers by Kṛṣṇa to see the thousand-headed form. By fallacious reasoning one should not accept the explanation that the form of Kṛṣṇa is inferior to the universal form, nor should one think that Arjuna had material eyes like other men, and therefore needed spiritual eyes to see the universal form. There are many references in the Mahābhārata and other scriptures stating that Arjuna was the avatāra of the Lord called Nara. Thus the two handed form of Kṛṣṇa is superior to the universal form.