The presentation of Vishnu in his cosmic form (Vishnu Vishvarupa) in the Changu Narayan Temple in Nepal goes back to the Bhagavadgita.  The Bhagavadgita is a part of the great Indian epic Mahabharata, and one of the most sacred and widely spread books of Hinduism. It describes the struggle of Arjuna with his relatives for the throne of the kingdom of Hastinapura. Literally, the Mahabharata, and also the Bhagavadgita, is a historical account of how the two related tribes fight for the rule of this kingdom.
This struggle can be mystically applied to the evolution of the individual human being, as well as to humanity as a whole. The two struggling tribes can be seen as the two possibilities anchored in man, one earthly-material, and one oriented towards spiritual development. Vishnu, in the incarnation of Krishna, teaches Arjuna – the part of man that is geared towards spiritual development – how to overcome the carvings and needs oriented towards material development. The battle described in the Bhagavadgita ... refers not only to the great warfare that mankind as a whole carries on but also to the struggle which is inevitable as soon as any single member in the human family resolves to allow his higher nature to govern him. 
The inner struggle of man
The conversation between Krishna and Arjuna takes place on the battlefield in the space between the two armies. In the form of Arjuna’s chariot driver, Krishna teaches Arjuna in 18 chapters about the different aspects of the path to devotion and overcoming the wheel of birth and death. Arjuna does not want to fight against his relatives and asks Krishna for advice. The latter emphasizes the inevitability of fighting and fulfilling one's duty. He advises Arjuna to fight and win his rightful kingdom. Mystically this seems to be the fight between the lower (earthly-material) and higher (oriented to spiritual development) self.
After various questions and doubts which Krishna answers, Arjuna comes to the point that he says: Thou alone knowest thyself by the Self … Thou alone can fully declare thy divine powers … How shall I, ... be able to know thee, o mysterious Lord?  In answer to this question, Krishna explains: I am the Ego, which is seated in the hearts of all beings, I am the beginning, the middle, and the end of all existing things ...  After this explanation, Arjuna asks to be allowed to see Krishna in his divine manifestation, and Krishna replies: ... behold … my forms by hundreds and thousands, of diverse kinds divine, of many shapes and fashions … as with thy natural eyes thou art not able to see me, I will give thee the divine eye. Behold my sovereign power and might. 
In a compelling vision, Arjuna is led by Krishna into a universe far beyond human perception. This vision of divine appearance is the theme of the Vishnu Vishvarupa sculpture of Changu Narayan. It is the interpretation of Arjuna's vision by the nameless artist who created this sculpture many centuries ago. It shows in the lower part the snake of eternity on which Vishnu rests in deep concentration in the cosmic ocean. In the upper part, Vishnu is shown as the ruler of all worlds with 10 heads. He is carried by elephants and his mount, the Garuda. Gods, goddesses, and half-gods pay homage to him. In his 10 arms, he holds the symbols of power, magic, and eternal knowledge. The representation of Vishnu is that of an exalted sun god who protects and preserves the world again and again and who has overcome death. In the Bhagavadgita, Krishna speaks to Arjuna after this vision: Thou hast seen this form of mine, which is difficult to be perceived and which even the gods are always anxious to behold. But I am not to be seen, in the way I have shown myself to thee, by the study of the Vedas, nor by mortification, nor alms-giving, nor sacrifices. I am to be approached and seen and known in truth by means of that devotion, which has me alone as the object.  With this, Krishna indicates the path of spiritual development. Is the temple Changu Narayan with its statues and sculptures the work of art that wants to lead to the realization of a new state of consciousness coming from another world?
The two sculptures discussed show the way to overcome suffering, illness, and death (Vishnu Trivikranta) and the goal, the resurrection (Vishnu Vishvarupa). They are two sculptures that radiate hope, confidence, and joy. They are works of art in the sense of the words mentioned in the introduction to this article. They also remind us of the words of Paul: "Death is swallowed in victory! Death, where is your sting?” 
Image: Horst Matthäus.
Swami Avinashananda summarizes Vishnu's apparitions as follows: Vishnu, the guardian of all, he whom none can deceive, made three strides and thenceforth established the dharma. As eyes behold the all-encompassing sky, so do the wise ones see the supreme state of Vishnu. The ever prayerful and awakened wise realizes the supreme state of Vishnu. 
 Bhagavadgita, The book of devotion; translated by William G. Judge; The Theosophy Company, Los Angeles, 1934 (https://archive.org/details/in.ernet.dli.2015.52397/page/n3/mode/2up)
.Ibid., Introduction, p. XV
 Ibid., Chap. X, p. 72
 Ibid., Chap.X, p. 73
 Ibid., Chap. XI, p. 78-79
 Ibid., Chap. XI, p. 88
 Paul, Corinthians 15, 55-56
 Avinashananda, Swami: Cultural Heritage of India, V.II Rig-Veda