Śrī brahma-saṁhitā 5.39
rāmādi-mūrtiṣu kalā-niyamena tiṣṭhan
nānāvatāram akarod bhuvaneṣu kintu
kṛṣṇaḥ svayaṁ samabhavat paramaḥ pumān yo
govindam ādi-puruṣaṁ tam ahaṁ bhajāmi
rāma-ādi — the incarnation of Lord Rāma, etc.; mūrtiṣu — in different forms; kalā-niyamena — by the order of plenary portions; tiṣṭhan — existing; nānā — various; avatāram — incarnations; akarot — executed; bhuvaneṣu — within the worlds; kintu — but; kṛṣṇaḥ — Lord Kṛṣṇa; svayam — personally; samabhavat — appeared; paramaḥ — the supreme; pumān — person; yaḥ — who; govindam — Govinda; ādi-puruṣam — the original person; tam — Him; aham — I; bhajāmi — worship.
I worship Govinda, the primeval Lord, who manifested Himself personally as Kṛṣṇa and the different avatāras in the world in the forms of Rāma, Nṛsiṁha, Vāmana, etc., as His subjective portions.
His subjective portions as the avatāras, viz., Rāma, etc., appear from Vaikuṇṭha and His own form Kṛṣṇa manifests Himself with Vraja in this world, from Goloka. The underlying sense is that Kṛṣṇa Caitanya, identical with Kṛṣṇa Himself, also brings about by His appearance the direct manifestation of Godhead Himself.