Matsya-avatāra: The Lord as Fish Saves the Vedas and Guides Satyavrata
योऽसावस्मिन् महाकल्पे तनय: स विवस्वत: । श्राद्धदेव इति ख्यातो मनुत्वे हरिणार्पित: ॥ ११ ॥
yo ’sāv asmin mahā-kalpe tanayaḥ sa vivasvataḥ śrāddhadeva iti khyāto manutve hariṇārpitaḥ
In this [the present] millennium King Satyavrata later became the son of Vivasvān, the king of the sun planet, and was known as Śrāddhadeva. By the mercy of the Supreme Personality of Godhead, he was given the post of Manu.
Śrāddhadeva is Vaivasvata Manu, the son of Vivasvān (the sun-god), appointed by Hari to serve as Manu for this manvantara.
To identify Manu’s lineage (son of Vivasvān) and to emphasize that the authority of Manu’s post comes from the Supreme Lord (Hari), who entrusts him with that responsibility.
It teaches that real authority and duty are meant to be accepted as a trust from God—so one should perform responsibilities as service to Hari, upholding dharma with humility.