Srimad-Bhagavatam: Canto 4 - Chapter 1 - Verse 6


एष साक्षाद्धरेरंशो जातो लोकरिरक्षया ।इयं च तत्परा हि श्रीरनुजज्ञेऽनपायिनी ॥ ६ ॥


eṣa sākṣād dharer aṁśojāto loka-rirakṣayāiyaṁ ca tat-parā hi śrīranujajñe ’napāyinī


In the form of King Pṛthu, the Supreme Personality of Godhead has appeared through a part of His potency to protect the people of the world. The goddess of fortune is the constant companion of the Lord, and therefore she has incarnated partially as Arci to become King Pṛthu’s queen.


In Bhagavad-gītā the Lord says that whenever one sees an extraordinary power, he should conclude that a specific partial representation of the Supreme Personality of Godhead is present. There are innumerable such personalities, but not all of them are direct viṣṇu-tattva plenary expansions of the Lord. Many living entities are classified among the śakti-tattvas. Such incarnations, empowered for specific purposes, are known as śaktyāveśa-avatāras. King Pṛthu was such a śaktyāveśa-avatāra of the Lord. Similarly, Arci, King Pṛthu’s wife, was a śaktyāveśa-avatāra of the goddess of fortune.