Shiva Purana

siva.sh/siva-purana/rudra-samhita/78/49

वरुणेन हयाः शुभ्रा ऋषिभिः कामकृत्तथा ।। सूर्येणोच्चैश्श्रवा दिव्यो भयात्तस्मै समर्पितः ।।४९।।

sanskrit

White horses were surrendered by Varuṇa, the wish-yielding cow Kāmadhenu by the sages, and the sun out of fear for him surrendered his divine horse Uccaiḥśravas.

english translation

varuNena hayAH zubhrA RSibhiH kAmakRttathA || sUryeNoccaizzravA divyo bhayAttasmai samarpitaH ||49||

hk transliteration by Sanscript