Page 47 - Complete Works of Dr. KCV Volume 1

The above shows that Time is conceived of the triple form, the first is daivika, the second is of the pitrs, and the last manava. The person who understands the mystic unity of the transcendence of the Prajapati and how He works in and through the twofold energies or souls and Matter will find that immortality is open to him. The five nights (ratris) above stated, namely Rayi, Candramas, Daksinayana, Krishnapaksa, and Ratri are of the downward path, the path that leads to disintegration and darkness and Ignorance. The contrary movement is that of the Ascent (or the Souls) in a sense. He who would know the mystic unity of these two in and through the Supreme is the Seer and Knower.
Sometimes it is difficult to gather the intention of these description at all. But the illustration granted by the Ramayana and Harivamsa is extremely valuable. If we look at the birth of Rama as described by Valmiki we find that he is born of the (in the) Five Pranas or Daytimes - Agni-Prana, (Aditya), Surya-Vamsa, Uttarayana, Suklapaksa, and Midday (karkataka lagna in Chaitra); and so also we find that Sri Krishna was born of (in) five Nights: Devaki (Rayi) Chandra-vamsa, Daksinayana, Krishnapaksa midnight. The supreme purpose of these two descents is to establish the kingdom of Truth and Dharma and abolition of unrighteousness and evil. The significance of these two avataras must be found in two different phases of the mystical Consciousness. The Divine is always the Prana. The descent into a lighted world is where the dharmas are very clear and determined and the people know them with clarity and Rama Rajya prevailed. The interference with this dharma and rajya was punished and the ancient order was restored. Certainly it was the exploit of the Mahavira Rama that we witness in his super human ability in slaying the ten headed Ravana of great prowess. Sri Rama revealed that he could and would protect everyone and no power on earth could prevent that.
In the case of Sri Krishna it was a period of great indeterminateness. Mankind was itself afflicted with unrighte-ousness. The Dvapara was at its end. It was the beginning of the Kali Night - the night among the yugas. The descent of Krishna was the descent of the supremest power which alone could plunge into inconcience and perennial darkness and in plunging illumine it at every level of its septi-planal darkness and above.