Vishnu was originally one of a Trinity who were considered aspects of one universal God, much as the Christian Trinity is considered to be three Persons in One. In Christianity we have God the Father, God the Son, Christ, and the Holy Spirit or Holy Ghost. In India they had Brahma, the Creator, Vishnu, the Preserver, and Siva, the Destroyer, all aspects of the One.
Vishnu was also called the Soul of the Universe, and the Compassionate. Thus he was identified with the ideas of Eternity and Love. As time passed, the importance of the Trinity in Hindu religion declined, and Vishnu assumed more and more the character of the All-in-AII. According to Yogi Ramacharaka, in his Philosophies and Religions of India, Vishnu was pictured in early Vedic literature as a gracious deity, filled with goodness, righteousness and love, as well as a desire for order and peace. The followers of Vishnu in later times became known as the Vishnuites or Vaishnavas. There also continued to be worshippers of Shiva, who were known as the Shivaites or Shaivas .
In Christianity the remoteness of the Godhead from human life made men desire an intermediary, and this need was filled by Christ, the Divine Son, who became a man and dwelt among us. In the same way the Hindus developed the worship of two incarnations of Vishnu, Rama and Krishna, who were representations of Vishnu in Hindu thought. Today in India Krishna is named a thousand times where Vishnu is named once. This also parallels the Christian practice. It does not mean that Vishnu is not understood to be the All-in-AII. (Introduction-The God Within)

I come to you from the universal ocean of vitality, from the Gateway of Eternity in this, the universal vibration, that hovers within all the galaxies and constellations, not in the dimension of space but in the vibrational spectrum that ascends from this, your earth condition, to the very apex, the tiny thread of creativity. It is my purpose to serve you in these moments when all vibrational influences are in direct alignment with what we are trying to achieve: the understanding of the brotherhood of man; of the full meaning of your existence and that of all men, and the full understanding of the principles governing all interrelated lives that will bring the reactions of every individual to the highest possible point of perfection...
...And this intercourse must be hastened in every way, for I come at a critical moment, and yet only for a short stay. We must use our vibrational opportunity, for the time is near when I cannot come at the bidding and request of the world. So I enter here that we may communicate, even though we may find defeat in the fear (the scepticism) that conquers the brain of mankind. (1st Dialogue)