Vishnupurana 2.11.9

2.11.9

māsi māsi ravir yo yas tatra tatra hi sā parā
trayīmayī viṣṇuśaktir avasthānaṃ karoti vai //

PARÁŚARA.--I will explain to you, Maitreya, the subject of your inquiry. The sun, though identified with the seven beings in his orb, is distinct from them as their chief. The entire and mighty energy of Vishńu, which is called the three Vedas, or Rich, Yajush, and Sáman, is that which enlightens the world, and destroys its iniquity. It is that also which, during the continuance of things, is present as Vishńu, actively engaged in the preservation of the universe, and abiding as the three Vedas within the sun. The solar luminary, that appears in every month, is nothing else than that very supreme energy of Vishńu which is composed of the three Vedas, influencing the motions of the planet; for the Richas (the hymns of the Rig-veda) shine in the morning, the prayers of the Yajush at noon, and the Vrihadrathantara and other portions of the Sáman in the afternoon. This triple impersonation of Vishńu, distinguished by the titles of the three Vedas, is the energy of Vishńu, which influences the positions of the sun.