Udyoga-parva Adhyāya 64: Arjuna’s Instruction to Sanjaya
Message to the Kuru Assembly
वासुदेवो<पि दुर्धर्षो यतात्मा यत्र पाण्डव: | अविषटद्दां पृथिव्यापि तद् बल॑ यत्र केशव:,जहाँ अपने मन और इन्द्रियोंको संयममें रखनेवाला दुर्धर्ष वीर पाण्डुपुत्र अर्जुन है, वहीं वसुदेवनन्दन श्रीकृष्ण भी रहते हैं और जिस सेनामें साक्षात् श्रीकृष्ण विराज रहे हों, उसका वेग समस्त भूमण्डलके लिये भी असहा हो जाता है
vāsudevo 'pi durdharṣo yatātmā yatra pāṇḍavaḥ | aviṣahyaṃ pṛthivyāpi tad balaṃ yatra keśavaḥ ||
Vidura declares that where the self-controlled, unconquerable Pāṇḍava Arjuna stands, Vāsudeva (Kṛṣṇa) is also present; and any force in which Keśava himself abides becomes so irresistible that even the whole earth would be unable to endure its onrush.
विदुर उवाच
True power is not merely numerical or physical; it arises from self-mastery (yatātmā) allied with righteous counsel and divine presence (Kṛṣṇa). Such a combination makes a cause ethically and practically formidable.
In the Udyoga Parva’s pre-war counsel, Vidura warns about the strength on the Pāṇḍavas’ side: Arjuna’s disciplined heroism together with Kṛṣṇa’s presence makes their force irresistible, implying the folly of opposing them unjustly.