"Sri Krishna Caitanya, Prabhu Nityananda, Sri Advaita, Gadadhara, and Srivas are the Five Truths, or Pancatattva. 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" (C.C.Adi 7.5)
"Let me offer my obeisances unto Lord Sri Krishna, who has manifested Himself in five as a devotee (Lord Caitanya), expansion of a devotee (Lord Nityananda), incarnation of a devotee (Advaita Acarya), pure devotee (Srivas), and devotional energy (Gadadhara)" (C.C.Adi 7.6)
Sri Caitanya Mahaprabhu
"The loving affairs of Sri Radha and Krishna are transcendental manifestations of the Lord’s internal pleasure-giving potency. Although Radha and Krishna are one in Their identity, They separated Themselves eternally. Now these two transcendental identities have again united, in the form of Sri Krishna Caitanya. I bow down to Him, who has manifested Himself with the sentiment and complexion of Srimati Radharani, although He is Krishna Himself." (C.C.Adi 1.5)
"Desiring to understand the glory of Radharani’s love, the wonderful qualities in Him that She alone relishes through Her love, and the happiness She feels when She realizes the sweetness of His love, the Supreme Lord Hari, richly endowed with Her emotions, appeared from the womb of Srimati Saci devi as the moon appeared from the ocean" (C.C.Adi 1.6)
Lord Caitanya Mahaprabhu is the source of energy for all His devotees. He is maha-vadanyavatara, the most magnanimous incarnation of the Lord, for He does not consider the offenses of the fallen souls. In order to take full benefit of the Hare Krishna Mahamantra, we must first take shelter of Sri Caitanya Mahaprabhu.
Sri Nityananda Prabhu
"May Sri Nityananda Rama be the object of my constant remembrance. Sankarsana, Sesa Naga and the Visnus who lie on the Karana Ocean, Garbha Ocean and Ocean of Milk are His plenary portions and the portions of His plenary portions." (C.C.Adi 1.7)
"I surrender unto the lotus feet of Sri Nityananda Rama, who is known as Sankarsana in the midst of the catur-vyuha [consisting of Vasudeva, Sankarsana, Pradyumna and Aniruddha]. He possesses full opulences and resides in Vaikunthaloka, far beyond the material creation." (C.C.Adi 1.8)
"I offer my full obeisances unto the feet of Sri Nityananda Rama, whose partial representation called Karanadakasayi Visnu, lying on the Karana Ocean, is the original Purusa, the master of the illusory energy, and the shelter of all the universes." (C.C.Adi 1.9)
"I offer my full obeisances unto the feet of Sri Nityananda Rama, a partial part of whom is Garbhodakasayi Visnu. From the navel of Garbhodakasayi Visnu sprouts the lotus that is the birthplace of Brahma, the engineer of the universe. The stem of that lotus is the resting place of the multitude of planets." (C.C.Adi 1.10)
"I offer my respectful obeisances unto the feet of Sri Nityananda Rama, whose secondary part is the Visnu lying in the Ocean of Milk. That Ksirodakasayi Visnu is the Supersoul of all living entities and the maintainer of all the universes. Sesa Naga is His further subpart" (C.C.Adi 1.11)
Devotees understand that Lord Nityananda is Balarama Himself — the first expansion of Krishna.
Vrindavan das Thakur, author of Caitanya Bhagavat prays, “I offer my respectful obeisances unto Sri Caitanya Mahaprabhu and Sri Nityananda Prabhu, whose long arms extend to Their knees. They have splendid golden complexions, and They inaugurated the congregational chanting of The Holy Names of the Lord. Their eyes resemble the petals of lotus flowers. They are the maintainers of all the worlds, the best of the brahmanas, the protectors of religious principles for this age. They bring happiness to the people of the world, and are the most merciful incarnations.”