advaitam acyutam anädim ananta-rüpam ādyaṁ purāṇa-puruṣaṁ nava-yauvanaṁ ca
Brahma-saṁhitā informs us that the Supreme Lord Sri Krishna, who is absolute, infallible, and without beginning, expands Himself into unlimited forms: ananta-rūpam. Sri Krishna has unlimited forms. Srimad Bhāgavatam compares the innumerable incarnations of the Lord to the rivulets flowing from inexhaustible sources of water.
avatārā hy asaṅkhyeyā hareḥ sattva-nidher dvijāḥ yathāvidāsinaḥ kulyāḥ sarasaḥ syuḥ sahasraśaḥ avatārā hy asaṅkhyeyā:
It is not possible to count. But they are all one. They are described as aṁśa-kalāḥ: plenary expansions or parts of the plenary expansions. Krishna is the fountainhead of all incarnations:
ete cāṁśa-kalāḥ puṁsaḥ kṛṣṇas tu bhagavān svayaṁ In the Chaitanya Charitamrita it is mentioned: ekale īśvara kṛṣṇa, āra saba bhṛtya:
Krishna alone is the Supreme Personality of Godhead, and all others, not only the living entities, even the various other forms of Krishna are His servitors. The various incarnations of the Lord appear in this material world with a very specific mission to accomplish. Their activities are extraordinary. No other human being can perform such activities.
Srila Prabhupada says:
The Lord is the inexhaustible source for innumerable incarnations which are distinguished by specific extraordinary feats which are impossible to be performed by any living being.
As mentioned earlier, each and every incarnation of the Lord has a particular mission, and they are all described in the revealed scriptures. The Lord appeared as Matsya, Kūrma, Varāha, Narasiṁha, Vāmana, and many others: and every time He had a specific purpose or mission to execute. When the whole world was deep within the water He appeared in the form of a fish and protected King Satyavrata and gave him transcendental knowledge. When the devatās and asurās churned the milk ocean using the Mandarācala Hill as the churning rod, He appeared in the form of a tortoise to hold the hill by serving as a pivot. When the demon Hiranyaksha dislocated the Earth from its orbit and threw it into the Garbhodhaka Ocean, the Lord appeared in the form of a wild boar to the rescue. He appeared in the half-man, half-lion form (Narasiṁha) to protect Prahlāda, and later on He appeared in the form of a dwarf-brāhmaṇa (Vāmana) to deliver Bali Mahārajā, the grandson of Prahlāda Mahārā Even the future incarnations of the Lord and the purpose of His advent are clearly mentioned in scriptures like Srimad Bhāgavatam. It is predicted that at the end of Kali-yuga, Lord Kalki will appear as the son of Vishnu Yasha, in the village of Shambala, to destroy the degraded, sinful men.
