Mahabharata 4.11.7

4.11.7

aśvānāṃ prakṛtiṃ vedmi vinayaṃ cāpi sarvaśaḥ |
duṣṭānāṃ pratipattiṃ ca kṛtsnaṃ caiva cikitsitam || 7 ||

"Virata said, 'I will give thee vehicles, wealth, and spacious quarters. Thou shalt be the manager of my horses. But first tell me whence thou comest, who thou art, and how also thou happenest to come here. Tell us also all the arts thou art master of.' Nakula replied, 'O mower of enemies, know that Yudhishthira is the eldest brother of the five sons of Pandu. I was formerly employed by him to keep his horses. I am acquainted with the temper of steeds, and know perfectly the art of breaking them. I know also how to correct vicious horses, and all the methods of treating their diseases. No animal in my hands becometh weak or ill. Not to speak of horses, even mares in my hands will never be found to be vicious. People called me Granthika by name and so did Yudhishthira, the son of Pandu.'