सखेति मत्वा प्रसभं यदुक्तं हे कृष्ण हे यादव हे सखेति। अजानता महिमानं तवेदं मया प्रमादात्प्रणयेन वापि ॥

sakheti matvā prasabhaṁ yad uktaṁ he kṛiṣhṇa he yādava he sakheti ajānatā mahimānaṁ tavedaṁ mayā pramādāt praṇayena vāpi

If, thinking Thee but friend, importunate, O Krishna! or O Yâdava! O friend! I cried, unknowing of Thy majesty, And careless in the fondness of my love;

In plain words: Arjuna remembers that he used to treat Krishna as just a friend. He called him casual names like 'Krishna' or 'friend' out of love, without knowing how great he really was.