Atharvaveda 12.1.37

12.1.37

yā́pa sarpáṃ vijámānā vimŕ̥gvarī yásyām ā́sann agnáyo yé apsv àntáḥ |
párā dásyūn dádatī devapīyū́n índraṃ vr̥ṇānā́ pr̥thivī́ ná vr̥trám śakrā́ya dadhre vr̥ṣabhā́ya vŕ̥ṣṇe ||37||

She who, cleansing one, trembling away the serpent; on whom were the fires that are within the waters, abandoning the god-insulting barbarians, choosing, she the earth, Indra [and] not Vṛitra, kept herself (dhṛ) for the mighty one (çakrá), the virile bull.