Mbh 6.106.1a

Sanjaya said, “Beholding Bhishma excited with wrath in battle, surrounded on all sides by the Pandavas like the Sun in the firmament, O king, by the clouds at the end of summer, Duryodhana, O monarch, addressed Dussasana, saying, ‘This heroic and great bowman Bhishma, this slayer of heroes, hath, O bull of Bharata’s race, been surrounded on all sides by the brave Pandavas. It is thy duty, O hero, to protect that illustrious one. Protected by us in battle, our grandsire Bhishma will slay all the Panchalas along with the Pandavas. The protection of Bhishma, therefore, I think, is our highest duty, for this great bowman of his vows, viz., Bhishma, is our protector in return. Therefore, surrounding the grandsire with all our troops, do thou protect him, who always achieveth the most difficult feats in battle.’ Thus addressed by Duryodhana, thy son Dussasana, surrounding Bhishma with a large force on all sides took up his position. Then Suvala’s son Sakuni, with hundreds and thousands of horsemen having bright spears and swords and lances in hand, and who formed a proud, well-dressed, and strong body bearing standards, and who were mingled with excellent foot-soldiers that were all well-trained and skilled in battle began to cheek Nakula, and Sahadeva, and Yudhishthira the son of Pandu, surrounding those foremost of men on all sides. Then king Duryodhana despatched ten thousand (other) brave horsemen for resisting the Pandavas. When these rushed like so many Garudas towards the enemy with great impetuosity, the earth, O king, struck with their horse-hoofs, trembled and uttered a loud noise. And the loud clatter of their hoofs was heard resembling the noise made by a large forest of bamboos, in conflagration on a mountain. And as these dashed over the field, there rose a cloud of dust, which rising to the welkin shrouded the very Sun.