Shloka 79
Atithi-satkāra and the Consolation of Wise Counsel (अतिथिसत्कारः प्रज्ञानवचनस्य च पराश्वासनम्)
कृषामि मेदिनीं पार्थ भूत्वा कार्ष्णायसो महान् | कृष्णो वर्णश्व॒ मे यस्मात् तस्मात् कृष्णोडहमर्जुन
kṛṣāmi medinīṃ pārtha bhūtvā kārṣṇāyaso mahān | kṛṣṇo varṇaś ca me yasmāt tasmāt kṛṣṇo 'ham arjuna ||
噢，帕尔塔（阿周那）！我化作以黑铁铸成的巨大犁铧，耕治大地。又因我身色亦黝黑，故人称我为“黑天”（Kṛṣṇa），噢，普利塔之子阿周那。
तामिन्द्र उवाच गच्छ नहुषस्त्वया वाच्योथ<पूर्वेण मामृषियुक्तेन यानेन त्वमधिरूढ
Educational Q&A
The verse grounds a revered name in concrete qualities—work and nature—suggesting that identity and honor can be understood through one’s function (tilling/sustaining the earth) and inherent attributes (dark complexion), not merely through lineage or status.
The speaker addresses Arjuna and explains the designation “Kṛṣṇa” by giving two reasons: he ‘ploughs the earth’ as a great dark-iron implement, and his own complexion is dark; thus the name arises from both action and appearance.