Atri Muni unspecifically thought of the Personality of Godhead, the Lord of the universe, although he had no clear idea of the Lord of the universe nor of His specific form. Mahā-Viṣṇu, from whose breathing millions of universes emanate and into whom they are again withdrawn, may be accepted as the Lord of the universe. Garbhodakaśāyī Viṣṇu, from whose abdomen sprouted the lotus flower which is the birthplace of Brahmā, may also be considered the Lord of the universe. Similarly, Kṣīrodakaśāyī Viṣṇu, who is the Supersoul of all living entities, may also be considered the Lord of the universe. Then, under the order of Kṣīrodakaśāyī Viṣṇu, the Viṣṇu form within this universe, Lord Brahmā and Lord Śiva may also be accepted as the Lords of the universe.
Viṣṇu is the Lord of the universe because He is its maintainer. Similarly, Brahmā creates the different planetary systems and the population, so he also may be considered the Lord of the universe. Or Lord Śiva, who is ultimately the destroyer of the universe, also may be considered its Lord. Therefore, since Atri Muni did not specifically mention whom he wanted, all three—Brahmā, Viṣṇu and Lord Śiva—came before him. They said, "Since you were thinking of having a son exactly like the Supreme Personality of Godhead, the Lord of the universe, your determination will be fulfilled." In other words, one's determination is fulfilled according to the strength of one's devotion. As stated in Bhagavad-gītā (BG 9.25): yānti deva-vratā devān pitṟn yānti pitṛ-vratāḥ. If one is attached to a particular demigod, one is promoted to the abode of that demigod; if one is attached to the Pitās, or forefathers, one is promoted to their planet; and similarly if one is attached to the Supreme Personality of Godhead, Kṛṣṇa, one is promoted to the abode of Lord Kṛṣṇa. Atri Muni had no clear conception of the Lord of the universe; therefore the three presiding deities who are actually the lords of the universe in the three departments of the modes of nature all came before him. Now, according to the strength of his determination for a son, his desire would be fulfilled by the grace of the Lord.