jiṣṇuś ca tad-darśana-jāta-sādhvasaḥ
tāv āha bhūmā parameṣṭhināṁ prabhur
beddhāñjalī sa-smitam ūrjayā girā
Śrīla Viśvanātha Cakravartī makes the following observations on this verse: Just as Lord Kṛṣṇa offered obeisances to His own Deity during the worship of Govardhana Hill, so now also He paid homage to His Viṣṇu expansion for the purpose of playing out His pastimes. The Lord is ananta, possessed of countless manifestations, and this eight-armed form is among them. He is acyuta, “never falling from His position,” in the sense that He never stops engaging in His humanlike pastimes as a cowherd boy of Vṛndāvana. Thus to safeguard the special sanctity of His humanlike pastimes as Kṛṣṇa, He offered obeisances to His own plenary expansion.
Lord Mahā-Viṣṇu appeared before Kṛṣṇa and Arjuna as bhūmā, the supremely opulent one, and as parameṣṭhināṁ prabhuḥ, the Lord of multitudes of Brahmās ruling over millions of universes. With solemn authority He spoke in such a way as to bewilder Arjuna, in obedience to Śrī Kṛṣṇa’s intention. His smile hinted at His private thoughts, which Śrīla Viśvanātha Cakravartī has revealed for our benefit: “My dear Kṛṣṇa, by Your desire I will describe My superiority, even though I am Your expansion. At the same time, however, I will subtly imply in My statements the supreme position of Your beauty, character and power and the fact that You are the source from which I emanate. Just see how clever I am — that in front of Arjuna I am confidentially divulging My true identity as nondifferent from You.”