In plain words
To one who has gone hungry for ten days, as if a good meal had come his way; when the water of tanks and wells has failed, as if rain had poured down day after day; to one who grieves at having no child, as if a son of merit had been born; to the poor man who writhes for want of food, as if a feast had fallen to him: on the earth, where Dharma was perishing, God has come to birth to protect the good. What else is there that I could make known beyond this, O members of this assembly, honoured for your saintly virtues!
Sahasra śīrṣā puruṣaḥ sahasrākṣa sahasrapāt: thousands of heads, thousands of eyes, thousands of feet; all these are the limbs of God. The whole world and every being are reflections of God. Unable to recognise that this sacred divinity is in himself, man makes efforts of many kinds to attain that divinity. Like one who fails to recognise the wish-fulfilling tree in his own backyard and runs to the neighbour's house for milk, man forgets the divinity within him and tries to search for God in the outer world alone.
When fire is burning in your own house, why go to the neighbour's for fire?
This is the very weakness that is in human nature.
The Avatāras are of two kinds. One is the Avatāra of a part. The second is the full Avatāra. All living beings are Avatāras of a part. 'Mamaivāṃśo jīva bhūta jīvaloka ssanātanaḥ': 'It is My part alone that is in all beings,' He has declared. But these partial Avatāras, bound by Māyā, develop the sense of mine and the principle of I, and live in this world in the jīva principle.