Life is incomplete without union with God. It's quite natural that a matured mind and blossomed heart strives for this union. From ages philosophies were born, debates happened, music, art and literature have sprung up from this need. Religions, philosophies, practices, customs and austerities have all pointed to one thing - union with the Divine.
The common man wakes up to the pain and suffering in his life and wants to be free from it. And he looks for the super power of creation to free him from the clutches of the world. The more he looks at the misery and shortcomings in his life, the farther away he feels from the Divinity, which is his very nature. And his heart yearns for some sort of communication from the other side. For time immemorial man has been striving to lessen this gap between himself and God. There are two ways to do this: one is to elevate mankind towards Divinity - this is called Siddha, one who has attained perfection and the second is to bring God to human level - Avatar, one who is not striving for perfection. Divinity has manifested itself for the sake of mankind. Man rising up to God is Siddha; God coming down, because he cares for you, is Avatar. To communicate directly with devotees, God comes in the form of Avatar.
Avatar is the humaneness where you can get a glimpse of Divinity. In the Puranas, all the devas are depicted with human emotions and tendencies. They do normal things - get upset, angry, are in love, etc. Rama and Krishna went through all the experiences of the human mind just to make you understand that God is not too far away from you, but one among you. Don't look for the supernatural in Avatar - then the whole purpose of coming close to humans is defeated. The expression of God's love for you on the most understandable human level is Avatar.
This concept of Avatar is prevalent in the east - India, China, Japan, Korea, Nepal etc. In these eastern countries, the monarch is revered as Avatar. Nripo Narayano Hari - the king is regarded as Avatar of Vishnu; Vaidhyo Narayano Hari - the doctor is regarded as Avatar of Vishnu. In the west, the concept is that of messenger, but in the east this concept does not exist as the intimacy between you and God is so much, God, himself, comes down. Like a mother would personally go to her child, God's love for man is so much, he would prefer to go Himself. The east looks from the value of the heart whereas the intellect has the perspective of messenger.
The concept of messenger was painful to bhaktas and Sufis - they are more comfortable with Avatar. For an intimate relationship, God comes directly. Your love for God becomes authentic when you are assured of his love for you. In Gita, it is Krishna who first tells Arjuna, 'You are dear to me', which enabled Arjuna to surrender.
Wherever you feel immense respect, wherever you get a glimpse of Divinity, know it is Avatar. Avatar lies in those who recognise - and the entire creation becomes alive as Divinity. This is the stage before the awareness of "I Am".
The entire phenomenon of creation is the descent of consciousness in various names and forms. And the whole purpose of Avatar is to make you realise that you are part of Him. Avatar is not there to charm you but to calm you, to make you return home.
And to make you realise you are that. Once you recognise the Avatar, suddenly the entire creation is filled with 'that' and you are that. The descent of God is to make you realise there is no up or down, there is no high or low, there is no ascension or descent! There is no two.