This thread is prompted by the thread 'The Suffering of the gods' initiated by Rahul which is presently under discussion. It's a brief compilation from the upanyAsa--lectures, of KAnchi ParamAchArya about 'Shankara Charitam'.

avatAra rahasyam

BhagavAn shrI KRShNa ParamAtma gives us enough hints in his Bhagavad GItA, as to why God should take avatar as a human being, when he could have as well accomplished the task by his saMkalpam--will, from where he is.

अजोऽपि सन्नव्ययात्मा भूतानामीश्वरोऽपि सन् ।
प्रकृतिं स्वामधिष्ठाय संभवाम्यात्ममायया ॥४.६॥

ajo&pi sannavyayAtmA bhUtAnAmIshvaro&pi san |
prakRutiM svAmadhiShThAya saMbhavAmyAtmamAyayA ||4.6||

Though I am unborn, of changeless nature and Lord of beings, yet subjugating my PrakRti, I come into being by my own mAyA. (Tr.svAmi svarUpAnanda, RK MaTham)

"I don't need to take janma--birth, getting stuck in karma. I am a birthless vastu--entity, ajaH. I am not a jIva that undergoes changes due to prakRti cheShTitaM--world set in motion, and the vikAras--vagaries, of manas--mind. I am the changeless Atma-vastu avyayAtman--imperishable Brahman. I am the Ishvara--Lord, of sakala bhUtas--all beings. Although I am in this way, I come into being, bringing the prakRti which is the AdhAra-kAraNam--supportive cause, substratum, of the appearance of this prapancham--universe, by my mAyA."

Just as he created the universe by his mAyA, he also apparently creates him as one who takes a birth. Although all this jIva-jaDa prapancham--universe of animate beings and inanimate matter, are all his appearances, and there is nothing else except him, he plays it in such a way that prakRti takes control of the jIva-jaDa prapancham, in whose sattva-raja-tamo guNas the jIvan gets stuck, indulges in karma and to experience its fruits takes birth after birth. On his part, however, he takes birth with complete control of the prakRti and ruling over it. That is what is known as an avatAram.

As to why he takes such avatarAm, he explains it in the most famous verse of the GItA:

यदा यदा हि धर्मस्य ग्लानिर्भवति भारत ।
अभ्युत्थानमधर्मस्य तदात्मानं सृजाम्यहम् ॥४.७॥

परित्राणाय साधूनां विनाशाय च दुष्कृताम् ।
धर्मसंस्थापनार्थाय सम्भवामि युगे युगे ॥४.८॥

yadA yadA hi dharmasya glAnirbhavati bhArata |
abhyutthAnamadharmasya tadAtmAnaM sRujAmyaham ||4.7||

paritrANAya sAdhUnAM vinAshAya cha duShkRutAm |
dharmasaMsthApanArthAya sambhavAmi yuge yuge ||4.8||

Whenever, O descendant of Bharata, there is decline of Dharma, and rise of Adharma, then I body myself forth.

For the protection of the good, for the destruction of the wicked, and for the establishment of Dharma, I come into being in every yuga. (Tr.svAmi svarUpAnanda, RK MaTham)

Many people take the meaning of the verse 4.8 that God's avatar happens only once in a yuga. It is not so. The 'yuge yuge' in this pair of verses matches with the 'yadA yadA', the opening of the first. Since 'yadA yadA' means 'whenever', 'yuge yuge' means 'in every yuga' and not only once in a yuga.

BhagavAn takes avatar to destroy adharma and establish dharma whenever the need arises. But why can't he do it just with his saMkalpam is the question.

Why did he say "prakRutiM svAm adhiShThAya" when talking about his taking avatar in verse 4.6? In verse 9.8, where he talks about giving birth to jIvas in the cycle that follows a kalpa, he uses a similar phrase: "prakRutiM svAm avaShTabhya"--animating my prakRti. Therein lies the sUchana--hint, for BhavAn's mAnuSha avatAra rahasyam.

Why not correct the world by mere saMkalpam?

Alright, adharma increas in the world and people who follow dharma suffer immensely at the hands of the adharmic forces. Instead of taking avatar a man among the people, BhagavAn could as well have set right things just his divine will? Why should he become a man, make efforts like us, indulge in samsAra--worldly life, fight and do saMhAra--killing, undergo all the tribulations of an avatar? Not only that; in his avatar as man, he behaves mentally like him: feeling angry, crying, doing shRnggAram--amorous behaviour? Why all these for a God of his stature?

If it is thought over deeply as to why he does not do it by mere saMkalpam, we would come to the conclusion that in that case he could have as well closed his sRShTi--Creation!

After all he has undertaken his sRShTi with a desire towards lIlA--sport, play, after initially remaining for indeterminable eons of time as "ekaM sva advitIyam"--"one without a second". Now with his desire of lIlA, he observes that status of ekam, only after the time of pralaya--dissolution, for one thousand chatur yugas and lets the sRShTi last eternally, so why should he close it?

Suppose he does not close his sRShTi opts to set the world right just by his divine will, then there will be only dharma the world over! People would lead a dharmic life, there would be no fresh karma added, and eventually when all the existing karmic balance is exhausted, the sRShTi will be dead by itself!

Since BhagavAn requires his sRShTi-lIlA, he does not destroy all adharma at once to last all times. Still the question remains unanswered: he could have set things right albeit temporarily when adharma is at peak and kept the duality of the world going. Why should he descend to the earth in human form for this task?

If we think this over, we would understand that after all both dharma and adharma are all due to his saMkalpam. He only shows it in kArya rUpam--form of acts, as everyone of us doing something. Have we read anywhere that the world became adharmic by his mere saMkalpam? In his scripting of life, the world becomes adharmic only due to the activities of the asuras, rAkShasas, duShTa rAjas--evil kings, those who preach wrong religous concepts and many other groups such as the thieves, killers and forgers. In this kali yuga, the reason for the acts of people done with their hands and legs is their corrupt mind. Thus it is shown in Ishvara lIlA that everything--both bad and good--is done by the mental and physical activities of indidual people and not by mere Ishvara saMkalpam. When adharma could increase to a peak by individual people, why should dharma alone be established by mere Ishvara saMkalpam?

Thus, when the dharmic balance is upset, BhagavAn sends his messengers in the form of sages. When the situation is beyond their scope, he himself takes avatar in human form.

The humanity and divinity of avatAra

When BhagavAn takes avatar in human form for dharmOttAraNam--rescue of dharma, he has kept kneaded into that very concept many things that are juicy to ponder. If the upadesham of dharma is to be done, the man who does it should live it and teach by the example of his own life. Only when the general public comes across an Adarsha puruSha--illustrating man, they would be motivated to emulate him in, atleast in thoughts.

Although an Adharsha puruSha, an avatar cannot remain in his own level at all times. If he does it, he can't be a model. Only when he descends to the level of the people, lead a normal life among them with all the worldly circumstances and emotional flux, and show that he is unaffected by such vRtti and vAsanas--behaviour and impressions, and act his part to match theirs, his life by example would shine by contrast and make the people emulate him in their thoughts and practices.

By living the life of a normal human being, exposing his divine powers only when absolutely necessary, the avatAra teaches us the potentiality of the manuShya shakti--human power, to transcend the worldly life, obtain chitta-shuddhi--mental purity, and become eligible for the sAdhana towards mokSha.

We are all BhagavAn's children. He is our unseen mAta-pitA. Just as we have desire to see our ultimate parent, he also has the desire to mingle physically with his children and give them the bliss of meeting their divine parent in person.

In this sRshTi-lIlA, BhagavAn created the asura lokam--world of demons where everything is adharmic. He created the deva, gandharva lokas--world of Devas and Gandharvas, where everything is pleasant. He created the tapolokam--world of Rishis, where everywhere there is shAnti--peace; and satyalokam--world of BrahmA, where everything is perfect. This world of ours, the bhUmi--earth, in his creation, is known as the mishra lokam--mixed world, so it remains as the ideal playground for his lIlAs and avatars.

The concept of avatarA is one of the main tenets of Hinduism. When a Hindu reads the life and lIlA of an avatarA and has occasion to doubt or question certain activities, he/she should ponder over the explanations given above and clear any misgivings.