Bhagavad Gita · Chapter 11: The Vision of the Cosmic Form
Bhagavad Gita 11.41
सखेति मत्वा प्रसभं यदुक्तं
हे कृष्ण हे यादव हे सखेति ।
अजानता महिमानं तवेदं
मया प्रमादात्प्रणयेन वापि ॥
sakheti matvā prasabhaṃ yaduktaṃ he kṛṣṇa he yādava he sakheti | ajānatā mahimānaṃ tavedaṃ mayā pramādātpraṇayena vāpi ||
Thinking of you as a friend, and not knowing this greatness of yours, whatever I have said rashly, out of carelessness or simply out of affection, calling you "Krishna," "Yadava," "my friend";
Modern context
Now Arjuna remembers all the times he called Krishna simply 'Krishna', 'Yadava', 'my friend', without knowing who he was. He is embarrassed and sorry. This is one of the most human moments in the Gita. Many people have had a similar shock: discovering that someone they took for granted was far greater than they realised, and wishing they had treated them with more reverence.