In the universal form of the Lord there is not even a trace of passion/action (rajas) and ignorance (tamas). It is in the form of pure existence (suddha sattva) which is beyond any form of comparison. In other words, it is the form of total purity.
Paśyanty ado rūpam adabhra-cakṣuṣā
This universal form (Virad roopa) of the Lord glows resplendently in His earrings. Great saints see this Universal form of the Lord with their transcendental eye (jnana netra).
This Universal form i.e. the incarnation as Adi Nārāyana, is the foremost of all incarnations. From Him, many incarnations emerge and after the completion of their purpose, they merge back into Him! This universal form is a fractional part of the Supreme Lord. Lord Brahma emerged as a fractional aspect of this Supreme Lord. From Him came Marichi and other eminent Maharishis. From them are born celestials, humans, animals, birds and all other forms of living beings.
24 incarnations of the Lord:
First incarnation: Lord Adi Nārāyana, who is the Universal form, accepted the forms of eminent Maharishis Sanaka, Sananda, Sanātana and Sanat kumara. In these four forms He practiced the most difficult and strenuous vow of Brahmacharya (walking on the path to realize God) without any hindrances.
Incarnation as a boar: The Supreme Lord is the Yagneshwara i.e. the Lord of all sacrificial rituals/ Yagnas. For the well-being of this earth He accepted the form of the boar (Yagna-varāha). He lifted and rescued the earth which had sunk into the nether regions (pātāla).
Incarnation as Maharishi Nārada: In the creation filled with saints, Lord Sriman Nārāyaṇa incarnated as the divine saint Maharishi Nārada. He taught to the devotees the Pancarātrāgama, which talks about actions (karma).
In the normal course, actions are the cause for all bondages. But due to adherence to good deeds (sat karmas) taught by Maharishi Nārada, the mind gets purified. This becomes conducive for attaining liberation. Through this approach, the Supreme Lord in the form of Nārada, preached liberation itself!
Incarnation as Nara-Nārayana: In the fourth incarnation, the Supreme Lord was born as Nara and Nārāyaṇa, the sons of King Dharma. These Maharishis totally controlled their minds and undertook severe strenuous austerities that were impossible for others to accomplish.
Incarnation as Maharishi Kapila: The Lord incarnated as Kapila Maharishi, the Lord of all Siddhas. He defined all the principles (tattvas) and preached the Sānkhya Shastra to Maharishi Āsuri. In course of time, this sacred scripture has vanished.
Incarnation as Dattātreya: The sixth incarnation of the Lord was Dattātreya, the Son of Maharishi Atri. He was born to Mother Anasuya as an answer to her prayers. He taught the knowledge of the Self to Alarka, Prahlada, Yadu, Kartavirya and others.
Incarnation as Yagna: The Lord incarnated as Yagna, the son of Prajapati Ruci and his wife Ākuti. Together with his sons Yāma and other divine troops he saved the period of time known as Swāyambhuva manvantara. Yajna was the seventh incarnation.
Incarnation as Rṣabha: The Lord who is all pervading and who can take huge steps, incarnated as Rṣabha, the Son of King Nābhi and his wife Merudevi. To those who possess right judgment and discriminative capacity he showed the path of ultimate knowledge which is revered by people from all orders of life.
Om Namo Narayana.