Atharvaveda 13.2.28

13.2.28

átandro yāsyán haríto yád ā́sthād dvé rūpé kr̥ṇute rócamānaḥ |
ketumā́n udyánt sáhamāno rájāṃsi víśvā āditya praváto ví bhāsi ||28||

When, about to go unwearied, he hath approached (ā-sthā) his yellow steeds, he, shining (ruc), makes for himself two forms; rising rich in lights (ketú-), overpowering the dim spaces (rájas), thou illuminest (vi-bhā), O Āditya, all the advances.