Bhagavad Gita: Chapter 1, Verse 12

तस्य सञ्जनयन्हर्षं कुरुवृद्ध: पितामह: |
सिंहनादं विनद्योच्चै: शङ्खं दध्मौ प्रतापवान् || 12||

tasya sañjanayan harṣhaṁ kuru-vṛiddhaḥ pitāmahaḥ
siṁha-nādaṁ vinadyochchaiḥ śhaṅkhaṁ dadhmau pratāpavān

tasyahis; sañjanayancausing; harṣhamjoy; kuru-vṛiddhaḥthe grand old man of the Kuru dynasty (Bheeshma); pitāmahaḥgrandfather; sinha-nādamlion’s roar; vinadyasounding; uchchaiḥvery loudly; śhaṅkhamconch shell; dadhmaublew; pratāpa-vānthe glorious


BG 1.12: Then, the grand old man of the Kuru dynasty, the glorious patriarch Bheeshma, roared like a lion, and blew his conch shell very loudly, giving joy to Duryodhan.


Grandsire Bheeshma understood the fear in his grand-nephew’s heart, and out of his natural compassion for him, he tried to cheer him by blowing his conch shell very loudly. Although he knew that Duryodhan had no chance of victory due to the presence of the Supreme Lord Shree Krishna on the other side, Bheeshma still let his nephew know that he would perform his duty to fight, and no pains would be spared in this connection. In the code of war at that time, this was the inauguration of the battle.