Some devotees are of the opinion that Krsna is an incarnation of Narayana, but the Bhagavata school says that Narayana is a manifestation of Krsna

Expressions researched:
"Some devotees are of the opinion that Kṛṣṇa is an incarnation of Nārāyaṇa, but the Bhāgavata school says that Nārāyaṇa is a manifestation of Kṛṣṇa"

Srimad-Bhagavatam

SB Canto 4

Lord Kṛṣṇa in His Nārāyaṇa feature is always four handed. On the Battlefield of Kurukṣetra, when Arjuna wanted to see His universal form, He showed this feature of four-handed Nārāyaṇa. Some devotees are of the opinion that Kṛṣṇa is an incarnation of Nārāyaṇa, but the Bhāgavata school says that Nārāyaṇa is a manifestation of Kṛṣṇa.

SB 4.8.47, Translation and Purport

The Lord is further described as having the mark of Śrīvatsa, or the sitting place of the goddess of fortune, and His bodily hue is deep bluish. The Lord is a person, He wears a garland of flowers, and He is eternally manifest with four hands, which hold [beginning from the lower left hand] a conchshell, wheel, club and lotus flower.

Here in this verse the word puruṣam is very significant. The Lord is never female. He is always male (puruṣa). Therefore the impersonalist who imagines the Lord's form as that of a woman is mistaken. The Lord appears in female form if necessary, but His perpetual form is puruṣa because He is originally male. The feminine feature of the Lord is displayed by goddesses of fortune—Lakṣmī, Rādhārāṇī, Sītā, etc. All these goddesses of fortune are servitors of the Lord; they are not the Supreme, as falsely imagined by the impersonalist. Lord Kṛṣṇa in His Nārāyaṇa feature is always four handed. On the Battlefield of Kurukṣetra, when Arjuna wanted to see His universal form, He showed this feature of four-handed Nārāyaṇa. Some devotees are of the opinion that Kṛṣṇa is an incarnation of Nārāyaṇa, but the Bhāgavata school says that Nārāyaṇa is a manifestation of Kṛṣṇa.