Śrī Kṛṣṇa has two types of manifestations, namely sound form, śabda-brahma and His personal form, param-brahma—śabda-brahma paraṁ brahma mamobhe śāśvatī tanū (SB 6.16.51). Maitreya says that when Bhagavān Viśṇu appeared to the sage Kardama it was his Śabda-brahma that appeared in personalized form – darśyāmāsa taṁ kṣattaḥ śābdaṁ brahma dadhad vapuh (SB 3.21.8). The conch in the hand of Bhagavān Viṣṇu is also considered as a representation of Śabda-brahma. This is understood from Viṣṇu touching the cheek of boy Dhruva after which the latter recited prayers. The conch is called brahma-maya by Maitreya (SB 4.9.4).
Śrīmad Bhāgavata, however, is a direct manifestation of Bhagavān Kṛṣṇa Himself. Śrī Sūta Gosvāmī calls Śrīmad Bhāgavata “the lamp that illuminates the Absolute Reality” (tattva-dīpaṁ purāṇam, SB 12.12.68). He also calls it “the light [or the direct revealer] of supreme transcendence” (adhyātma-dīpam, SB 1.2.3), as well as “the unparalleled lamp of transcendental knowledge” (atulo jñāna-pradīpaḥ, SB 12.13.19). In Devakī’s prayers to Kṛṣṇa when He appeared in the prison of Kaṁsa, she refers to Him as “the lamp of spiritual knowledge” (adhyātma-dīpaḥ, SB 10.3.24). These statements imply that Śrīmad Bhāgavata and Śrī Kṛṣṇa both are adhyātma-dīpaḥ and thus nondifferent. This fact is further confirmed by Sūta Gosvāmī in his reply to the following pertinent question of Śaunaka Ṛṣi:
Now that Śrī Kṛṣṇa, the Master of yoga, the well-wisher of the brāhmaṇas, and the protector of dharma, has departed to His own paramount abode, please tell us to whom dharma has gone for refuge. (SB 1.1.23)
Sūta Gosvāmī’s reply given below makes it evident that Śrīmad Bhāgavata appeared as Kṛṣṇa’s direct representative (tat-pratinidhi-rūpeṇāvirbabhūva):
Upon Śrī Kṛṣṇa’s departure to His own abode, accompanied by dharma, transcendental knowledge (jñāna), and other divine majesties, this self-effulgent Sun in the form of the Bhāgavata Purāṇa has now arisen for those bereft of sight in the age of Kali. (SB 1.3.43)
In Padma Purāṇa, while describing the glories of Śrīmad Bhāgavata, the Kumāras inform sage Nārada: “This Purāṇa called Śrīmad Bhāgavata is indeed directly Śrī Kṛṣṇa and none else” (Uttara-khaṇḍa 198.30). Accordingly, in Skanda Purāṇa, it is stated: “The Śrīmad Bhāgavata and Śrī Bhagavān [Kṛṣṇa] share an eternal absolute oneness of essential nature (svarūpa), characterized as unalloyed being (sat), consciousness (cit), and divine bliss (ānanda)” (Viṣṇu-khaṇḍa 6.4.3). Such being the case, the twelve cantos of Śrīmad Bhāgavata are equated with the twelve parts of Śrī Kṛṣṇa’s transcendental body:
Kṛṣna’s two feet are the First and Second Cantos, His two thighs are the Third and Fourth Cantos, His navel area is the Fifth Canto. His chest is the Sixth Canto, and His two arms are the Seventh and Eight Cantos. O King, Kṛṣna’s throat is the Ninth Canto, His smiling lotus face is the Tenth Canto, His forehead is the Eleventh Canto, and His head is the Twelfth Canto. I worship Him, the Primeval Deva, the repository of compassion, whose bodily hue resembles a Tamāla tree, whose avatāric descent is meant for the highest good of all living beings, who is the bridge to cross over the limitless ocean of worldly existence, and who is directly manifest in the form of Śrīmad Bhāgavata.
Thus for Gauḍīya Vaiṣṇavas, Śrīmad Bhāgavata is not just a book but Śrī Kṛṣṇa manifest in the form of sound. Śrīmad Bhāgavata is worshipable like Kṛṣṇa Himself. It is said that Sanātana Gosvāmī considered Śrīmad Bhāgavata as his iṣṭa-devatā even before meeting Śrī Caitanya Mahāprabhu.