Bhagavad Gita 1.14
Then, seated in their spacious war chariot, yoked with white horses, Lord Shri Krishna and Arjuna sounded their divine conch shells.
ततः श्वेतैर्हयैर्युक्ते महति स्यन्दने स्थितौ।
माधवः पाण्डवश्चैव दिव्यौ शङ्खौ प्रदध्मतुः॥tataḥ śvetairhayairyukte mahati syandane sthitau|
mādhavaḥ pāṇḍavaścaiva divyau śaṅkhau pradadhmatuḥ||
English translation (above): Shri Purohit Swami (1935), public domain. Sanskrit text via github.com/gita/gita (Unlicense).