Bhagavad Gita
4.4

अर्जुन उवाच | अपरं भवतो जन्म परं जन्म विवस्वतः | कथमेतद्विजानीयां त्वमादौ प्रोक्तवानिति ||४||

arjuna uvācha aparaṁ bhavato janma paraṁ janma vivasvataḥ katham etad vijānīyāṁ tvam ādau proktavān iti

Translation

Arjuna said: The sun-god Vivasvan is senior by birth to You. How am I to understand that in the beginning You instructed this science to him?

Interpretation

Arjuna raises a valid apparent contradiction: Vivasvan (the sun-god) existed long before Krishna's current incarnation. How could Krishna have taught him? This question opens the doorway to Krishna's most stunning revelation about the nature of his divine identity.