CC Ādi 7.5

pañca-tattva — eka-vastu, nāhi kichu bheda
rasa āsvādite tabu vividha vibheda
Synonyms: 
pañca-tattva — the five subjects; eka-vastu — they are one in five; nāhi — there is not; kichu — anything; bheda — difference; rasa — mellows; āsvādite — to taste; tabu — yet; vividha — varieties; vibheda — differences.
Translation: 
Spiritually there are no differences between these five tattvas, for on the transcendental platform everything is absolute. Yet there are also varieties in the spiritual world, and in order to taste these spiritual varieties one should distinguish between them.
Purport: 

In his Anubhāṣya commentary Śrī Bhaktisiddhānta Sarasvatī Ṭhākura describes the Pañca-tattva as follows: The supreme energetic, the Personality of Godhead, manifesting in order to enjoy five kinds of pastimes, appears as the members of the Pañca-tattva. Actually there is no difference between them because they are situated on the absolute platform, but they manifest different spiritual varieties as a challenge to the impersonalists to taste different kinds of spiritual humors (rasas). In the Vedas it is said, parāsya śaktir vividhaiva śrūyate: “The varieties of energy of the Supreme Personality of Godhead are differently known.” From this statement of the Vedas one can understand that there are eternal varieties of humors, or tastes, in the spiritual world. Śrī Gaurāṅga, Śrī Nityānanda, Śrī Advaita, Śrī Gadādhara and Śrīvāsa Ṭhākura are all on the same platform, but in spiritually distinguishing between them one should understand that Śrī Caitanya Mahāprabhu is the form of a devotee, Nityānanda Prabhu appears in the form of a devotee’s spiritual master, Advaita Prabhu is the form of a bhakta (devotee) incarnation, Gadādhara Prabhu is the energy of a bhakta, and Śrīvāsa Ṭhākura is a pure devotee. Thus there are spiritual distinctions between them. The bhakta-rūpa (Śrī Caitanya Mahāprabhu), the bhakta-svarūpa (Śrī Nityānanda Prabhu) and the bhakta-avatāra (Śrī Advaita Prabhu) are described as the Supreme Personality of Godhead Himself, His immediate manifestation and His plenary expansion, and They all belong to the Viṣṇu category. Although the spiritual and marginal energies of the Supreme Personality of Godhead are nondifferent from the Supreme Personality of Godhead Viṣṇu, they are predominated subjects, whereas Lord Viṣṇu is the predominator. As such, although they are on the same platform, they have appeared differently in order to facilitate tasting of transcendental mellows. Actually, however, there is no possibility of one being different from the other, for the worshiper and the worshipable cannot be separated at any stage. On the absolute platform, one cannot be understood without the other.